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