Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
peterui » peterdi (Expand Search)
petrou » peterou (Expand Search), petruou (Expand Search), petroou (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrui » peterui (Expand Search), petruui (Expand Search), petroui (Expand Search)
petruo » peteruo (Expand Search), petruuo (Expand Search), petrouo (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 ((perov OR peterov) OR (((petrou OR (petri OR (petrui OR peterui))) OR petruo) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((perov OR peterov) OR (((petrou OR (petri OR (petrui OR peterui))) OR petruo) OR petr)) o.s.*".