Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
peri » petri (Expand Search), per (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petrooi (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petruo » peteruo (Expand Search), petriuo (Expand Search), petrouo (Expand Search)
petrouo » peterouo (Expand Search), petriouo (Expand Search), petroouo (Expand Search)
petr » peter (Expand Search), petri (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 (perov OR ((((peri OR petroi) OR petru) OR (petruo OR petrouo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (perov OR ((((peri OR petroi) OR petru) OR (petruo OR petrouo)) OR petr)) o.s.*".