References: Logic Gates and Digital Signals

1. Logic gate - Wikipedia - Comprehensive overview of logic gates, symbols, truth tables, and implementations.

2. CMOS - Wikipedia - Detailed explanation of CMOS technology used in modern digital circuits.

3. Functional completeness - Wikipedia - Mathematical foundations explaining why NAND and NOR gates alone can implement any Boolean function.

4. Digital Design (6th Edition) - M. Morris Mano and Michael Ciletti - Pearson - Chapter 3 covers logic gates, gate characteristics, and IC families.

5. Logic Gates - All About Circuits - Comprehensive coverage of all gate types with truth tables, symbols, and timing characteristics.