List of 4000-series integrated circuits

Last updated

The following is a list of CMOS 4000-series digital logic integrated circuits . In 1968, the original 4000-series was introduced by RCA. Although more recent parts are considerably faster, the 4000 devices operate over a wide power supply range (3V to 18V recommended range for "B" series) and are well suited to unregulated battery powered applications and interfacing with sensitive analogue electronics, where the slower operation may be an EMC advantage. The earlier datasheets included the internal schematics of the gate architectures and a number of novel designs are able to 'mis-use' this additional information to provide semi-analog functions for timing skew and linear signal amplification. [1] Due to the popularity of these parts, other manufacturers released pin-to-pin compatible logic devices and kept the 4000 sequence number as an aid to identification of compatible parts. However, other manufacturers use different prefixes and suffixes on their part numbers, and not all devices are available from all sources or in all package sizes.

Contents

Overview

CD4001B quad 2-input NOR gate in DIP-14 package, manufactured by National Semiconductor in 1983 ANT Nachrichtentechnik DBT-03 - National Semiconductor CD4001BCJ-0020.jpg
CD4001B quad 2-input NOR gate in DIP-14 package, manufactured by National Semiconductor in 1983

Non-exhaustive list of manufacturers which make or have made these kind of ICs.

Current manufacturers of these ICs:

Former manufacturers of these ICs:

Logic gates

Pinout of 4049 hex inverter gates, and pinout compatible with 4050 buffer 4049 Pinout.svg
Pinout of 4049 hex inverter gates, and pinout compatible with 4050 buffer
Pinout of 4093 quad
2-input NAND gates with
schmitt trigger inputs, and
pinout compatible with 4011 4093 Pinout.svg
Pinout of 4093 quad
2-input NAND gates with
schmitt trigger inputs, and
pinout compatible with 4011

Since there are numerous 4000-series parts, this section groups related combinational logic parts to make it easier for the reader to choose part numbers.

All parts in this section have normal inputs and push-pull outputs, unless stated differently.

One input voltage translation gates:

One input logic gates:

Two to eight input logic gates:

ConfigurationANDNANDORNORXORXNOR
Quad 2-Input408140114071400140704077
Triple 3-Input4073402340754025n/an/a
Dual 4-Input4082401240724002n/an/a
Single 8-Input4068406840784078n/an/a
Note: The 4068 & 4078 has two outputs Q and Q. The 4048 is an 8-input gate too (see below). The 4572 has a NOR gate and NAND gate (see above).

AND-OR-Invert (AOI) logic gates:

When configured as AND-OR-INVERT (AOI) gate, it will reduce the boolean expression ABCD + EFGH + EXPAND.
When configured as AND-OR (AO) gate, it will reduce the boolean expression ABCD + EFGH + EXPAND.
When configured as NOR gate, it will reduce the boolean expression A + B + C + D + E + F + G + H + EXPAND, which is a 9-input NOR gate when EXPAND is used as a 9th input.
When configured as OR gate, it will reduce the boolean expression A + B + C + D + E + F + G + H + EXPAND, which is a 9-input OR gate when EXPAND is used as a 9th input.
Note: The 4041 can simplify AOI boolean expression implementations by providing buffered A, B, C, D and A, B, C, D.

Parts list

This list consists mostly of part numbers from a 1983 RCA databook, though the leading "CD" and tailing letters (A, B, UB) have been removed for generic part number use. The numeric portion of part numbers from some manufactures may not be identical to generic part numbers in this table. Motorola typically prepended a "1" and removed the first "0" from part numbers within the range of 40100 to 40199, such as RCA CD40174B becomes Motorola MC14174B.

Part numberCategoryUnitsDescription of 4000 to 4099PinsDatasheet
4000Logic Gates2Dual 3-input NOR gate + One inverter gate 14 RCA
4001Logic Gates4Quad 2-input NOR gate14 RCA, TI
4002Logic Gates2Dual 4-input NOR gate14 RCA, TI
4006Shift Registers118-stage shift register (four independent with common clock: two 4-stage, two 5-stage with Q4 tap)14 RCA
4007Analog/Digital2Dual complementary enhanced-MOS transistor pair + 1 inverter gate 14 RCA, TI
4008Math14-bit binary full adder 16 RCA
4009Logic Gates6Hex inverter gate, dual power supply, can drive 1 TTL/DTL load (replaced by 4049)16 RCA, TI
4010Logic Gates6Hex buffer gate, dual power supply, can drive 1 TTL/DTL load (replaced by 4050)16 RCA, TI
4011Logic Gates4Quad 2-input NAND gate 14 RCA, TI
4012Logic Gates2Dual 4-input NAND gate14 RCA, TI
4013Flip-Flops2Dual D-type flip-flop, Q & Q outputs, positive-edge trigger, asynchronous set and reset14 RCA, TI
4014Shift Registers18-stage parallel in shift register (synchronous parallel load, serial in, Q6/Q7/Q8 out) (see 4021 for asynchronous)16 RCA, TI
4015Shift Registers2Dual 4-stage shift register (two independent: serial in, Q1/Q2/Q3/Q4 out, reset, clock)16 RCA, TI
4016Analog Switches4Quad bilateral switch 14 RCA, TI
4017Counters1Decade counter (5-stage Johnson counter) with 10-output decoder, active HIGH output (see 4022 for octal)16 RCA, TI
4018Counters1Presettable divide-by-N counter16 RCA, TI
4019Logic Gates4Quad AND-OR select gate 16 RCA, TI
4020Counters114-stage binary ripple counter 16 RCA, TI
4021Shift Registers18-stage parallel in shift register (asynchronous parallel load, serial in, Q6/Q7/Q8 out) (see 4014 for synchronous)16 RCA, TI
4022Counters1Octal counter (4-stage Johnson counter) with 8-output decoder, active HIGH output (see 4017 for decade)16 RCA, TI
4023Logic Gates3Triple 3-input NAND gate 14 RCA, TI
4024Counters17-stage binary ripple counter 14 RCA, TI
4025Logic Gates3Triple 3-input NOR gate 14 RCA, TI
40267-Segment Decoders1Decade counter with decoded 7-segment display outputs and display enable16 RCA, TI
4027Flip-Flops2Dual J-K master-slave flip-flop, Q & Q outputs, positive-edge trigger, asynchronous set and reset16 RCA, TI
4028Multiplexers14-bit BCD to 10-output decoder (can be used as 3-bit binary to 8-output decoder), active HIGH output16 RCA, TI
4029Counters1Presettable up/down counter, binary or BCD-decade16 RCA, TI
4030Logic Gates4Quad XOR gate (replaced by 4070)14 RCA, TI
4031Shift Registers164-stage shift register 16 RCA, TI
4032Math3Triple serial adder16 RCA
40337-Segment Decoders1Decade counter with decoded 7-segment display outputs and ripple blanking16 RCA, TI
4034Registers18-stage bidirectional parallel/serial input/output register24 RCA, TI
4035Shift Registers14-stage parallel-in/parallel-out shift register16 RCA, TI
40373Triple AND-OR bi-phase pairs14 RCA
4038Math3Triple serial adder16 RCA
4040Counters112-stage binary ripple counter16 RCA, TI
4041Logic Gates4Quad buffer/inverter (2 outputs per gate) (4 times standard "B" drive)14 RCA, TI
4042Latches4Quad D-type latch, Q & Q outputs, positive or negative edge trigger depending on polarity pin, shared clock16 RCA, TI
4043Latches4Quad NOR R-S latch, Q outputs, three-state outputs16 RCA, TI
4044Latches4Quad NAND R-S latch, Q outputs, three-state outputs16 RCA, TI
4045Counters121-stage counter16 RCA, TI
4046PLL1 Phase-locked loop with VCO 16 RCA, TI
4047Timers1 Monostable/astable multivibrator, external RC oscillator14 RCA, TI
4048Logic Gates1Single expandable 8-input 8-function gate, three-state output,
choice of: NOR, OR, NAND, AND, AND-NOR (AOI), AND-OR, OR-NAND (OAI), OR-AND
16 RCA, TI
4049Logic Gates6Hex inverter gate, can drive two TTL/RTL loads or four 74LS loads16 RCA, TI
4050Logic Gates6Hex buffer gate, can drive two TTL/RTL loads or four 74LS loads16 RCA, TI
4051Analog Switches1Single 8-channel analog multiplexer/demultiplexer 16 RCA, TI
4052Analog Switches2Dual 4-channel analog multiplexer/demultiplexer16 RCA, TI
4053Analog Switches3Triple 2-channel analog multiplexer/demultiplexer16 RCA, TI
4054LCD Drivers14-segment LCD driver with latch16 RCA, TI
4055LCD Drivers1BCD to 7-segment decoder/LCD driver with "display-frequency" output16 RCA, TI
4056LCD Drivers1BCD to 7-segment decoder/LCD driver with strobed-latch function16 RCA, TI
4057Math14-bit arithmetic logic unit (ALU)28 RCA
4059Counters1Programmable divide-by-N counter24 RCA, TI
4060Counters114-stage binary ripple counter, external RC or crystal oscillator (32.768 kHz compatible), schmitt trigger inputs16 RCA, TI
4061Memory1256x1 bit static RAM16 RCA
4062Shift Registers1200-stage dynamic shift register16 RCA
4063Math14-bit magnitude comparator 16 RCA, TI
4066Analog Switches4Quad analog switch (low "ON" resistance)14 RCA, TI
4067Analog Switches1Single 16-channel analog multiplexer/demultiplexer (1-of-16 switch)24 RCA, TI
4068Logic Gates1Single 8-input NAND/AND gate (2 outputs per gate)14 RCA, TI
4069Logic Gates6Hex inverter14 RCA, TI
4070Logic Gates4Quad 2-input XOR gate 14 RCA, TI
4071Logic Gates4Quad 2-input OR gate 14 RCA, TI
4072Logic Gates2Dual 4-input OR gate14 RCA, TI
4073Logic Gates3Triple 3-input AND gate 14 RCA, TI
4075Logic Gates3Triple 3-input OR gate14 RCA, TI
4076Registers4Quad D-type register, three-state outputs16 RCA, TI
4077Logic Gates4Quad 2-input XNOR gate 14 RCA, TI
4078Logic Gates1Single 8-input NOR/OR gate (2 outputs per gate)14 RCA, TI
4081Logic Gates4Quad 2-input AND gate 14 RCA, TI
4082Logic Gates2Dual 4-input AND gate14 RCA, TI
4085Logic Gates2Dual 2-wide, 2-input AND-OR-Invert (AOI)14 RCA, TI
4086Logic Gates1Single expandable 4-wide, 2-input AND-OR-Invert (AOI)14 RCA, TI
4089Rate Multipliers1Binary rate multiplier16 RCA, TI
4093Logic Gates4Quad 2-input NAND gate, schmitt trigger inputs14 RCA, TI
4094Shift Registers18-stage shift-and-store bus16 RCA, TI
4095Flip-Flops1Gated J-K flip-flop, Q & Q outputs, positive-edge trigger, asynchronous set and reset, non-inverting inputs14 RCA, TI
4096Flip-Flops1Gated J-K flip-flop, Q & Q outputs, positive-edge trigger, asynchronous set and reset, inverting and non-inverting inputs14 RCA, TI
4097Analog Switches1Single differential 8-channel analog multiplexer/demultiplexer24 RCA, TI
4098Timers2Dual one-shot monostable 16 RCA, TI
4099Latches18-bit addressable latch16 RCA, TI
Part numberCategoryUnitsDescription of 40100 to 40199PinsDatasheet
40100Shift Registers132-stage left/right shift register 16 RCA
40101Logic Gates19-bit parity generator 14 RCA
40102Counters1Presettable 2-decade BCD down counter16 RCA, TI
40103Counters1Presettable 8-bit binary down counter16 RCA, TI
40104Shift Registers14-bit bidirectional parallel-in/parallel-out shift register, three-state outputs16 RCA
40105Memory14-bit x 16 word FIFO register16 RCA, TI
40106Logic Gates6Hex inverter gate, schmitt trigger inputs14 RCA, TI
40107Logic Gates/Driver2Dual 2-input NAND gate, 136 mA open drain output driver (32 times standard "B" sink)8 RCA, TI
40108Memory14x4-bit synchronous triple-port register file, three-state outputs24 RCA
40109Voltage Translator4Quad voltage level translator, three-state outputs, dual power rails16 RCA, TI
401107-Segment Decoders1Up/down decade counter, latch, 7-segment decoder, LED driver16 RCA, TI
401172Dual programmable 4-bit terminator14 RCA, TI
40147110-line to 4-line (BCD) priority encoder 16 RCA, TI
40160Counters14-bit synchronous decade counter, asynchronous clear, load, ripple carry output16 RCA, TI
40161Counters14-bit synchronous binary counter, asynchronous clear, load, ripple carry output16 RCA, TI
40162Counters14-bit synchronous decade counter, synchronous clear, load, ripple carry output16 RCA, TI
40163Counters14-bit synchronous binary counter, synchronous clear, load, ripple carry output16 RCA, TI
40174Flip-Flops6Hex D-type flip-flop, Q outputs, positive-edge trigger, shared clock and clear16 RCA, TI
40175Flip-Flops4Quad D-type flip-flop, Q & Q outputs, positive-edge trigger, shared clock and clear16 RCA, TI
40181Math14-bit 16-function arithmetic logic unit (ALU)24 RCA
40182Math1 Look-ahead carry generator for four adders16 RCA
40192Counters1Presettable 4-bit up/down BCD counter16 RCA, TI
40193Counters1Presettable 4-bit up/down binary counter16 RCA, TI
40194Shift Registers14-bit bidirectional parallel-in/parallel-out shift register 16 RCA, TI
Part numberCategoryUnitsDescription of 40200 to 40299PinsDatasheet
40208Memory14 x 4-bit synchronous triple-port register file, three-state outputs24 RCA
40257Multiplexers4Quad 2-line to 1-line data selector/multiplexer, three-state outputs16 RCA, TI
Part numberCategoryUnitsDescription of 4500 to 4599PinsDatasheet
4500 1Industrial control unit (ICU), 1-bit microprocessor16 Motorola
4502Logic Gates6Hex strobed inverter, three-state outputs16 RCA, TI
4503Logic Gates6Hex buffer, three-state outputs16 RCA, TI
4504Voltage Translator6Hex voltage translator, TTL-to-CMOS or CMOS-to-CMOS, dual power rails16 TI
4508Latches2Dual 4-bit latch, Q outputs, three-state outputs24 RCA, TI
4510Counters1Presettable 4-bit BCD up/down counter16 RCA, TI
45117-Segment Decoders1BCD to 7-segment latch/decoder/LED driver16 RCA, TI
4512Multiplexers18-input multiplexer (data selector), three-state output16 RCA, TI
4514Multiplexers11-of-16 decoder/demultiplexer, active HIGH output24 RCA, TI
4515Multiplexers11-of-16 decoder/demultiplexer, active LOW output24 RCA, TI
4516Counters1Presettable 4-bit binary up/down counter16 RCA, TI
4517Shift Registers2Dual 64-stage shift register16 RCA, TI
4518Counters2Dual BCD up counter16 RCA, TI
4520Counters2Dual 4-bit binary up counter16 RCA, TI
4521Timers/Divider124-stage frequency divider, choice of external / RC / crystal oscillator, 18 thru 24 stage outputs16 TI
4522Counters1Programmable BCD divide-by-N counter16 TI
45271BCD rate multiplier16 RCA, TI
4531Logic Gates113-input parity checker/generator16 Philips
4532Multiplexers18-bit priority encoder, 3-bit output16 RCA, TI
4536Timers1Programmable timer, external clock or RC oscillator, choice of divider from 1 to 24 stages16 RCA, TI
4538Timers2Dual retriggerable precision monostable multivibrator, Q & Q outputs16 RCA, TI
4541Timers1Programmable timer, external clock or RC oscillator, choice of divider of 8 / 10 / 13 / 16 stages14 RCA, TI
4543LCD Drivers1BCD to 7-segment latch/decoder/LCD driver, phase input16 RCA, TI
4555Multiplexers2Dual 1-of-4 decoder/demultiplexer, active HIGH output16 RCA, TI
4556Multiplexers2Dual 1-of-4 decoder/demultiplexer, active LOW output16 RCA, TI
4572Logic Gates6Hex gates: quad inverter gate, single 2-input NAND gate, single 2-input NOR gate16 TI
4580Memory14 x 4-bit synchronous triple-port register file, three-state outputs24 Motorola
4584Logic Gates6Hex inverter gate, schmitt trigger inputs14 Onsemi
4585Math14-bit digital comparator 16 RCA, TI
Part numberCategoryUnitsDescription of 4700 to 4799PinsDatasheet
472418-bit addressable latch16 RCA, TI

See also

Related Research Articles

<span class="mw-page-title-main">Logic gate</span> Device performing a Boolean function

A logic gate is a device that performs a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, one that has, for instance, zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device.

Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors. Its name signifies that transistors perform both the logic function and the amplifying function, as opposed to earlier resistor–transistor logic (RTL) and diode–transistor logic (DTL).

<span class="mw-page-title-main">CMOS</span> Technology for constructing integrated circuits

Complementary metal–oxide–semiconductor is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. CMOS technology is used for constructing integrated circuit (IC) chips, including microprocessors, microcontrollers, memory chips, and other digital logic circuits. CMOS technology is also used for analog circuits such as image sensors, data converters, RF circuits, and highly integrated transceivers for many types of communication.

<span class="mw-page-title-main">Programmable logic device</span> Reconfigurable digital circuit element

A programmable logic device (PLD) is an electronic component used to build reconfigurable digital circuits. Unlike digital logic constructed using discrete logic gates with fixed functions, the function of a PLD is undefined at the time of manufacture. Before the PLD can be used in a circuit it must be programmed to implement the desired function. Compared to fixed logic devices, programmable logic devices simplify the design of complex logic and may offer superior performance. Unlike for microprocessors, programming a PLD changes the connections made between the gates in the device.

<span class="mw-page-title-main">Inverter (logic gate)</span> Logic gate implementing negation

In digital logic, an inverter or NOT gate is a logic gate which implements logical negation. It outputs a bit opposite of the bit that is put into it. The bits are typically implemented as two differing voltage levels.

<span class="mw-page-title-main">4000-series integrated circuits</span> Series of CMOS logic integrated circuits

The 4000 series is a CMOS logic family of integrated circuits (ICs) first introduced in 1968 by RCA. It was slowly migrated into the 4000B buffered series after about 1975. It had a much wider supply voltage range than any contemporary logic family. Almost all IC manufacturers active during this initial era fabricated models for this series. Its naming convention is still in use today.

In digital electronics, the fan-out is the number of gate inputs driven by the output of another single logic gate.

<span class="mw-page-title-main">7400-series integrated circuits</span> Series of transistor–transistor logic integrated circuits

The 7400 series is a popular logic family of transistor–transistor logic (TTL) integrated circuits (ICs).

<span class="mw-page-title-main">555 timer IC</span> Integrated circuit used for timer applications

The 555 timer IC is an integrated circuit used in a variety of timer, delay, pulse generation, and oscillator applications. It is one of the most popular timing ICs due to its flexibility and price. Derivatives provide two or four timing circuits in one package. The design was first marketed in 1972 by Signetics and used bipolar junction transistors. Since then, numerous companies have made the original timers and later similar low-power CMOS timers. In 2017, it was said that over a billion 555 timers are produced annually by some estimates, and that the design was "probably the most popular integrated circuit ever made".

Intersil is an American semiconductor company headquartered in Milpitas, California. As of February 24, 2017, Intersil is a subsidiary of Renesas. The previous Intersil was formed in August 1999 through the acquisition of the semiconductor business of Harris Corporation. Intersil is a power management IC business, with specialized capability in power management and precision analog technology for applications in industrial, infrastructure, mobile, automotive and aerospace.

The AND gate is a basic digital logic gate that implements logical conjunction (∧) from mathematical logic – AND gate behaves according to the truth table. A HIGH output (1) results only if all the inputs to the AND gate are HIGH (1). If not all of the inputs to the AND gate are HIGH, a LOW output results. The function can be extended to any number of inputs.

The OR gate is a digital logic gate that implements logical disjunction. The OR gate outputs "true" if any of its inputs is "true"; otherwise it outputs "false". The input and output states are normally represented by different voltage levels.

In digital electronics, a NAND gate (NOT-AND) is a logic gate which produces an output which is false only if all its inputs are true; thus its output is complement to that of an AND gate. A LOW (0) output results only if all the inputs to the gate are HIGH (1); if any input is LOW (0), a HIGH (1) output results. A NAND gate is made using transistors and junction diodes. By De Morgan's laws, a two-input NAND gate's logic may be expressed as , making a NAND gate equivalent to inverters followed by an OR gate.

XOR gate is a digital logic gate that gives a true output when the number of true inputs is odd. An XOR gate implements an exclusive or from mathematical logic; that is, a true output results if one, and only one, of the inputs to the gate is true. If both inputs are false (0/LOW) or both are true, a false output results. XOR represents the inequality function, i.e., the output is true if the inputs are not alike otherwise the output is false. A way to remember XOR is "must have one or the other but not both".

The NAND Boolean function has the property of functional completeness. This means that any Boolean expression can be re-expressed by an equivalent expression utilizing only NAND operations. For example, the function NOT(x) may be equivalently expressed as NAND(x,x). In the field of digital electronic circuits, this implies that it is possible to implement any Boolean function using just NAND gates.

The XNOR gate is a digital logic gate whose function is the logical complement of the Exclusive OR (XOR) gate. It is equivalent to the logical connective from mathematical logic, also known as the material biconditional. The two-input version implements logical equality, behaving according to the truth table to the right, and hence the gate is sometimes called an "equivalence gate". A high output (1) results if both of the inputs to the gate are the same. If one but not both inputs are high (1), a low output (0) results.

The NOR gate is a digital logic gate that implements logical NOR - it behaves according to the truth table to the right. A HIGH output (1) results if both the inputs to the gate are LOW (0); if one or both input is HIGH (1), a LOW output (0) results. NOR is the result of the negation of the OR operator. It can also in some senses be seen as the inverse of an AND gate. NOR is a functionally complete operation—NOR gates can be combined to generate any other logical function. It shares this property with the NAND gate. By contrast, the OR operator is monotonic as it can only change LOW to HIGH but not vice versa.

AND-OR-invert (AOI) logic and AOI gates are two-level compound logic functions constructed from the combination of one or more AND gates followed by a NOR gate. Construction of AOI cells is particularly efficient using CMOS technology, where the total number of transistor gates can be compared to the same construction using NAND logic or NOR logic. The complement of AOI logic is OR-AND-invert (OAI) logic, where the OR gates precede a NAND gate.

HCMOS is the set of specifications for electrical ratings and characteristics, forming the 74HC00 family, a part of the 7400 series of integrated circuits.

References

  1. "The Benefits of Ancient Logic | Analog Devices".
  2. "Standard Logic - Product View". onsemi.com. Retrieved 2016-04-28.
  3. "Logic Circuit | Register | Buffer | Driver | Gate | Overview | Logic | TI.com". ti.com. Retrieved 2016-04-28.
  4. "NXP - Logic - HEF4000 Series". nxp.com. Archived from the original on 2016-04-18. Retrieved 2016-04-28.
  5. "Renesas Electronics - CD4001BMS". renesas.com. Retrieved 2018-08-18.
  6. "Parametric Search | Intersil". intersil.com. Retrieved 2016-04-28.
  7. "Automotive Logic ICs - STMicroelectronics". www2.st.com. Retrieved 2016-04-28.
  8. "CMOS Logic ICs | TOSHIBA Semiconductor & Storage Products Company | Americas". toshiba.semicon-storage.com. Retrieved 2016-04-28.
  9. Schlenzig, Klaus; Ekne, Peter (1987) [1986]. "5. Digitale CMOS-Schaltkreisreihe V4000 - Eigenschaften und Anwendungen" [Series of digital CMOS integrated circuits V4000 (4000) - Properties and use cases]. In Erlekampf, Rainer; Mönk, Hans-Joachim (eds.). Mikroelektronik in der Amateurpraxis[Microelectronics for the practical amateur] (in German) (3 ed.). Berlin: Militärverlag der Deutschen Demokratischen Republik  [ de ], Leipzig. pp. 271, 280, 283–284, 298–300. ISBN   3-327-00357-2. 7469332. (NB. Among many other ICs of the U and V series, this discusses the U40501D, U40511D and V40511D.)
  10. "561ая серия" [561 series] (in Russian). Retrieved 2022-04-12.

Further reading