Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petrui » petri (Expand Search), pentrui (Expand Search), petrii (Expand Search), petriui (Expand Search), petroui (Expand Search), perui (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), petriu (Expand Search), petrou (Expand Search), peru (Expand Search)
petroiiu » petrioiiu (Expand Search), petrooiiu (Expand Search), peroiiu (Expand Search)
petroooiuo » petrioooiuo (Expand Search), petrooooiuo (Expand Search), peroooiuo (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (Expand Search)

Try widening your search to All Fields.

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 (petrui OR petru)) OR ((petroiiu OR petroooiuo) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR (petrui OR petru)) OR ((petroiiu OR petroooiuo) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR (petrui OR petru)) OR ((petroiiu OR petroooiuo) OR (petr OR peter))) o.s.*.