Dear Jukka,
There is a biography of Otto Kittel by Franz Kurowski, but it is in German. I have just looked at Amazon and there are two in English, but they are not available
https://www.amazon.de/KITTEL-GIFFARD...s=books&sr=1-2
https://www.amazon.de/Otto-Kittel-Ro...s=books&sr=1-3
And about Gordon Gollob there is nothing, I'm afraid.