Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
pero » petro (Expand Search), per (Expand Search), pro (Expand Search)
petroi » petro (Expand Search), petrov (Expand Search), petrow (Expand Search), petruoi (Expand Search), petrooi (Expand Search), peroi (Expand Search)
petero » peters (Expand Search), petro (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (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 ((((peteruo OR pero) OR petroi) OR (petero OR peter)) OR (petr OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petruov OR ((((peteruo OR pero) OR petroi) OR (petero OR peter)) OR (petr OR petri))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petruov OR ((((peteruo OR pero) OR petroi) OR (petero OR peter)) OR (petr OR petri))) o.s.*.