Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
petrioi » petruioi (Expand Search), petroioi (Expand Search), perioi (Expand Search)
petruioi » petruuioi (Expand Search), petrouioi (Expand Search), peruioi (Expand Search)
petris » petruis (Expand Search), petrois (Expand Search), peris (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (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 (((petruov OR (petrioi OR petruioi)) OR petris) OR ((petr OR petri) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petruov OR (petrioi OR petruioi)) OR petris) OR ((petr OR petri) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petruov OR (petrioi OR petruioi)) OR petris) OR ((petr OR petri) OR peter)) o.s.*.