Perhaps you should try some spelling variations:
petruv » petrov (Expand Search), pentruv (Expand Search), petrouv (Expand Search), peruv (Expand Search)
petruov » petrov (Expand Search), pentruov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
petru » pentru (Expand Search), petrou (Expand Search), peru (Expand Search)
petruo » pentruo (Expand Search), petrouo (Expand Search), peruo (Expand Search), petro (Expand Search)
petr » petro (Expand Search), per (Expand Search)
petri » petroi (Expand Search), peri (Expand Search)
petriuo » petroiuo (Expand Search), periuo (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 ((petruv OR petruov) OR (((((petru OR petr) OR petri) OR petruo) OR petriuo) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruv OR petruov) OR (((((petru OR petr) OR petri) OR petruo) OR petriuo) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruv OR petruov) OR (((((petru OR petr) OR petri) OR petruo) OR petriuo) OR peter)) o.s.*.