Perhaps you should try some spelling variations:
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petroi » peteroi (Expand Search), petruoi (Expand Search), petrooi (Expand Search), petro (Expand Search)
petrow » peterow (Expand Search), petruow (Expand Search), petroow (Expand Search), petro (Expand Search), petrowna (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrui » peterui (Expand Search), petruui (Expand Search), petroui (Expand Search), petru (Expand Search)
petrov » peterov (Expand Search), petruov (Expand Search), petroov (Expand Search), petro (Expand Search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: fop ((petr OR ((petroi OR petrow) OR (petri OR petrui))) OR petrov) _. s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petr OR ((petroi OR petrow) OR (petri OR petrui))) OR petrov) _. s.*".