What is the title of books that written by doctor feodor jagur?

There seems to be a misunderstanding. There is no widely known author named "Doctor Feodor Jagur". It's possible you're misremembering the name or there's a lesser-known author with a similar name.

To help me find the right author, could you tell me more? For example:

* What is the genre of the books you are looking for? (Fiction, non-fiction, medical, etc.)

* Do you remember any specific titles or characters from the books?

* Do you know anything else about the author, such as nationality or approximate time period of their work?

With more information, I might be able to help you find the author you're looking for.