digital logic - In a JK Binary Counter from 0 to 9, why is the NAND gate connected to the second and fourth J-K flip flop and not the first and fourth? -
verilog - Synchronous Counter using JK flip-flop not behaves as expected - Stack Overflow
Synchronous counter
How to design an asynchronous counter using JK flip for getting the following sequence 0-2-4-7-9-0 - Quora