Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
peru » petru (Expand Search), per (Expand Search)
peruui » petruui (Expand Search), perui (Expand Search)
peri » per (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrui » peterui (Expand Search), petruui (Expand Search), petroui (Expand Search)
petruui » peteruui (Expand Search), petruuui (Expand Search), petrouui (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 (((petri OR peru) OR ((peri OR petrui) OR (petruui OR peruui))) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (perov OR (((petri OR peru) OR ((peri OR petrui) OR (petruui OR peruui))) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (perov OR (((petri OR peru) OR ((peri OR petrui) OR (petruui OR peruui))) OR petr)) o.s.*.