Perhaps you should try some spelling variations:
petrov » petro (Expand Search), peterov (Expand Search), petriov (Expand Search), petroov (Expand Search)
petriov » petriv (Expand Search), petrisv (Expand Search), petrov (Expand Search), peteriov (Expand Search), petriiov (Expand Search), petroiov (Expand Search)
petrio » petri (Expand Search), petris (Expand Search), petro (Expand Search), peterio (Expand Search), petriio (Expand Search), petroio (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petro (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search), petri (Expand Search)
petrow » peterow (Expand Search), petriow (Expand Search), petroow (Expand Search), petro (Expand Search), petrowna (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 ((petriov OR petrov) OR ((peteruo OR petrio) OR (petr OR ((petru OR petrow) OR pentru)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petrov) OR ((peteruo OR petrio) OR (petr OR ((petru OR petrow) OR pentru)))) o.s.*".