Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petro » petrov (Expand Search), petero (Expand Search), pero (Expand Search)
petruv » peteruv (Expand Search), peruv (Expand Search)
petrv » peterv (Expand Search), perv (Expand Search)
petri » peteri (Expand Search), peri (Expand Search)
petru » peteru (Expand Search), peru (Expand Search)
petrio » peterio (Expand Search), perio (Expand Search)
petr » peter (Expand Search), per (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 petruv) OR petrv) OR ((((petro OR petri) OR petru) OR petrio) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((perov OR petruv) OR petrv) OR ((((petro OR petri) OR petru) OR petrio) OR petr)) o.s.*".