You seemed to hit a dead end when the book you are reading refers to Witting's Mathematische Statistik and you don't know German. It's kind of surprising nobody (even the author himself) thought about translating the book for wider public (English speaking) considering it is referred frequently.
Is it that the Soviet books are translated at a greater rate than the German ones? I have hardly come across any German translated mathematical statistics book. I have seen French being translated, though.
