Examples of Designing of Synchronous Mod-N Counters
Synchronous Counter and the 4-bit Synchronous Counter
Lessons In Electric Circuits -- Volume IV (Digital) - Chapter 11
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