Perhaps you should try some spelling variations:
petrov » petro (Expand Search), peterov (Expand Search), petroov (Expand Search), perov (Expand Search)
petr » peter (Expand Search), petro (Expand Search), per (Expand Search)
petrowi » peterowi (Expand Search), petroowi (Expand Search), perowi (Expand Search), petrowna (Expand Search), petroi (Expand Search), petrownai (Expand Search)
petrow » peterow (Expand Search), petroow (Expand Search), perow (Expand Search), petro (Expand Search), petrowna (Expand Search)
petru » peteru (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search)
petrou » peterou (Expand Search), petroou (Expand Search), perou (Expand Search), petro (Expand Search)
petri » peteri (Expand Search), petroi (Expand Search), peri (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 perov) OR (petr OR (((petrowi OR petrow) OR (petru OR petrou)) OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR perov) OR (petr OR (((petrowi OR petrow) OR (petru OR petrou)) OR petri))) o.s.*".