What books are you trying to find it in? An e4 repertoire for White?
Every Petroff book I have seen that is either objective (like the everyman book written in 2004ish) or book written for Black, like Cohen's book for New In Chess or the book that Chess Stars published, or the move by move book all cover it.
Hey,
I am unable to find much information about that particular opening. It's not talked about in the books or videos I have read/watched. Would be grateful if somebody shared knowledge to me about this opening. I play Petrov defence as black and am kinda lost if white chooses that particular steinitz attack route 3. d4.