Perhaps you should try some spelling variations:
petrov » petro (Expand Search), peterov (Expand Search), petruov (Expand Search), petroov (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
pero » petro (Expand Search), pro (Expand Search)
peterov » peterv (Expand Search), petrov (Expand Search)
petero » peter (Expand Search), petro (Expand Search)
peters » peter (Expand Search), petersen (Expand Search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: fop ((petrov OR peterov) OR ((((petr OR pero) OR petri) OR (petero OR peters)) OR per)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR peterov) OR ((((petr OR pero) OR petri) OR (petero OR peters)) OR per)) o.s.*".