Perhaps you should try some spelling variations:
petrov » peterov (Expand Search), petriov (Expand Search), petroov (Expand Search)
petruuov » peteruuov (Expand Search), petriuuov (Expand Search), petrouuov (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petriui » peteriui (Expand Search), petriiui (Expand Search), petroiui (Expand Search)
petruo » peteruo (Expand Search), petriuo (Expand Search), petrouo (Expand Search)
petr » peter (Expand Search), petri (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 ((petrov OR petruuov) OR (((((petru OR pero) OR petriui) OR petero) OR petruo) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR petruuov) OR (((((petru OR pero) OR petriui) OR petero) OR petruo) OR petr)) o.s.*".