Perhaps you should try some spelling variations:
petrov » petro (Expand Search), petroov (Expand Search), perov (Expand Search)
petriov » petroiov (Expand Search), periov (Expand Search)
petroio » petrooio (Expand Search), peroio (Expand Search)
petri » petroi (Expand Search), peri (Expand Search)
petriuo » petroiuo (Expand Search), periuo (Expand Search)
petr » petro (Expand Search), per (Expand Search)
petru » petrou (Expand Search), peru (Expand Search), pentru (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 ((petroio OR (petri OR petriuo)) OR ((petr OR petru) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petrov) OR ((petroio OR (petri OR petriuo)) OR ((petr OR petru) OR peter))) o.s.*".