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