Perhaps you should try some spelling variations:
petruv » petru (Expand Search), petrov (Expand Search), petruuv (Expand Search), petrouv (Expand Search), peruv (Expand Search)
petriov » petrov (Expand Search), petruiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petrui » petruui (Expand Search), petroui (Expand Search), perui (Expand Search), petru (Expand Search)
pero » petro (Expand Search), per (Expand Search), pro (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 petriov) OR petruv) OR (((petr OR pero) OR (petri OR petrui)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petruv OR petriov) OR petruv) OR (((petr OR pero) OR (petri OR petrui)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petruv OR petriov) OR petruv) OR (((petr OR pero) OR (petri OR petrui)) OR peter)) o.s.*.