Perhaps you should try some spelling variations:
petrov » peterov (Expand Search), petruov (Expand Search), petroov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrui » peterui (Expand Search), petruui (Expand Search), petroui (Expand Search)
petrio » peterio (Expand Search), petruio (Expand Search), petroio (Expand Search)
petruuio » peteruuio (Expand Search), petruuuio (Expand Search), petrouuio (Expand Search)
petr » peter (Expand Search), petru (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 (periov OR ((((petrov OR (petri OR petrui)) OR peruo) OR (petrio OR petruuio)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (periov OR ((((petrov OR (petri OR petrui)) OR peruo) OR (petrio OR petruuio)) OR petr)) o.s.*".