These seem very direct and not ultra advanced, good read.
- Quantum field theory lecture notes | 71, 262, 3
- Quantum field theory bibliography | 30, 1k, 29
- Quantum field theory | 329, 7k, 103
- Relativistic quantum mechanics | 99, 9k, 134
- Quantum mechanics | 170, 18k, 243
- Particle physics | 137, 28k, 458
- Physics | 276, 40k, 705
- Natural science | 0, 49k, 1k
- Science | 0, 53k, 1k
- Ciro Santilli's Homepage | 262, 182k, 3k
- Klein-Gordon equation | 243, 496, 1