Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petro » petrov (Expand Search), petri (Expand Search), petru (Expand Search), petero (Expand Search), petrio (Expand Search), petruo (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petriuui » peteriuui (Expand Search), petriiuui (Expand Search), petruiuui (Expand Search)
petriiuo » peteriiuo (Expand Search), petriiiuo (Expand Search), petruiiuo (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 ((((petruv OR petruv) OR perov) OR petruv) OR (((petro OR petriuui) OR petriiuo) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petruv OR petruv) OR perov) OR petruv) OR (((petro OR petriuui) OR petriiuo) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petruv OR petruv) OR perov) OR petruv) OR (((petro OR petriuui) OR petriiuo) OR petr)) o.s.*.