Perhaps you should try some spelling variations:
petriv » peteriv (Expand Search), petruiv (Expand Search), petroiv (Expand Search)
petrov » peterov (Expand Search), petruov (Expand Search), petroov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petroi » peteroi (Expand Search), petruoi (Expand Search), petrooi (Expand Search)
petruoi » peteruoi (Expand Search), petruuoi (Expand Search), petrouoi (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (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 ((petriv OR petrov) OR (((pero OR (petri OR (petroi OR petruoi))) OR petero) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriv OR petrov) OR (((pero OR (petri OR (petroi OR petruoi))) OR petero) OR petr)) o.s.*".