Perhaps you should try some spelling variations:
petrov » peterov (Expand Search), petriov (Expand Search), petruov (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search)
petruo » peteruo (Expand Search), petriuo (Expand Search), petruuo (Expand Search)
petruouo » peteruouo (Expand Search), petriuouo (Expand Search), petruuouo (Expand Search)
petriiuo » peteriiuo (Expand Search), petriiiuo (Expand Search), petruiiuo (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 (petrov OR (((pero OR petroi) OR ((petruo OR petruouo) OR petriiuo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petrov OR (((pero OR petroi) OR ((petruo OR petruouo) OR petriiuo)) OR petr)) o.s.*".