Perhaps you should try some spelling variations:
petrouov » petrov (Expand Search), peterouov (Expand Search), petriouov (Expand Search), petruouov (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search)
petrioi » peterioi (Expand Search), petriioi (Expand Search), petruioi (Expand Search)
petruoouo » peteruoouo (Expand Search), petriuoouo (Expand Search), petruuoouo (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 ((petruov OR petrouov) OR (((petroi OR petrioi) OR (peteruouo OR petruoouo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR petrouov) OR (((petroi OR petrioi) OR (peteruouo OR petruoouo)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR petrouov) OR (((petroi OR petrioi) OR (peteruouo OR petruoouo)) OR petr)) o.s.*.