flipflop - 2 Bit Synchronous circuit that operates only with clock [Q] - Electrical Engineering Stack Exchange
Counters | CircuitVerse
How to design a synchronous counter 4 bit using JK flip flop that can count up even numbers from 0 to 14, and count down odd numbers from 15 to 0 in 1 system - Quora
JK Flip Flop - Basic Online Digital Electronics Course
Logic diagram, operation, & timing diagram of a 2-bit Synchronous Counter