Perhaps you should try some spelling variations:
petrioov » petrov (Expand Search), peterioov (Expand Search), petriioov (Expand Search), petruioov (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petrouv » peterouv (Expand Search), petriouv (Expand Search), petruouv (Expand Search)
petriu » peteriu (Expand Search), petriiu (Expand Search), petruiu (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (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 ((petrioov OR (petruv OR petrouv)) OR ((((petriu OR peteru) OR pero) OR petroi) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrioov OR (petruv OR petrouv)) OR ((((petriu OR peteru) OR pero) OR petroi) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petrioov OR (petruv OR petrouv)) OR ((((petriu OR peteru) OR pero) OR petroi) OR petr)) o.s.*.