Perhaps you should try some spelling variations:
peterov » petrov (Expand Search), peterv (Expand Search), petersv (Expand Search)
petruv » petrov (Expand Search), peteruv (Expand Search), petrouv (Expand Search), peruv (Expand Search), pentruv (Expand Search)
petr » peter (Expand Search), petro (Expand Search), per (Expand Search)
petru » peteru (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search)
petri » peteri (Expand Search), petroi (Expand Search), peri (Expand Search)
petero » peter (Expand Search), peters (Expand Search), petro (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 ((peterov OR petruv) OR (((((petr OR petero) OR perio) OR petru) OR peruo) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((peterov OR petruv) OR (((((petr OR petero) OR perio) OR petru) OR peruo) OR petri)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((peterov OR petruv) OR (((((petr OR petero) OR perio) OR petru) OR peruo) OR petri)) o.s.*.