Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petro » petrov (Expand Search), petru (Expand Search), petero (Expand Search), petruo (Expand Search), pero (Expand Search)
petruv » peteruv (Expand Search), petruuv (Expand Search), peruv (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), peri (Expand Search)
petrio » peterio (Expand Search), petruio (Expand Search), perio (Expand Search)
petruuo » peteruuo (Expand Search), petruuuo (Expand Search), peruuo (Expand Search)
petr » peter (Expand Search), petru (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 peterov) OR petruv) OR ((((petro OR petri) OR petrio) OR petruuo) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((perov OR peterov) OR petruv) OR ((((petro OR petri) OR petrio) OR petruuo) OR petr)) o.s.*".