Derivation of Kramers-Heisenberg eq.

すんません，こんなタイトル書いたら，参考にするために世界の学生さんたちが集まってきそうだ（；ω；）

I am sorry I didn't achieve it yet.
（；ω；）

At first I have referred Sakurai and Messiah.
Because my target material (one review paper) cited those text book.

I feel such books for advanced QM is difficult for me, so I studied QP by Gasiorowicz.

It is succeeded to get backbone of quantization of EM and even derive some crucial part.

The goal is derivation of Kramers Heisenberg (Dirac) eq.
So I have come back to Skaurai and Messiah and ...

Oh god, I have lost way why I cannot go ahead from the first step only one step cannot step out （；ω；）

...now I am studying Gasiorowicz again.
I wonder I can reach the goal only by this book.

WHY.
（・ω・）？？

Oh god..