Perhaps you should try some spelling variations:
petruuov » petrov (Expand Search), peteruuov (Expand Search), petruuuov (Expand Search), petrouuov (Expand Search)
petruoov » petrov (Expand Search), peteruoov (Expand Search), petruuoov (Expand Search), petrouoov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petroi » peteroi (Expand Search), petruoi (Expand Search), petrooi (Expand Search)
petrui » peterui (Expand Search), petruui (Expand Search), petroui (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 ((petruuov OR petruoov) OR ((pero OR (((petri OR petroi) OR petrui) OR peteri)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruuov OR petruoov) OR ((pero OR (((petri OR petroi) OR petrui) OR peteri)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruuov OR petruoov) OR ((pero OR (((petri OR petroi) OR petrui) OR peteri)) OR petr)) o.s.*.