Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petruuov » petrov (Expand Search), peteruuov (Expand Search), petruuuov (Expand Search), petrouuov (Expand Search)
peru » petru (Expand Search), per (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrio » peterio (Expand Search), petruio (Expand Search), petroio (Expand Search)
petriio » peteriio (Expand Search), petruiio (Expand Search), petroiio (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)

Try widening your search to All Fields.

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 peteruiov) OR petruuov) OR (((petri OR peru) OR (petrio OR petriio)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((perov OR peteruiov) OR petruuov) OR (((petri OR peru) OR (petrio OR petriio)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((perov OR peteruiov) OR petruuov) OR (((petri OR peru) OR (petrio OR petriio)) OR petr)) o.s.*.