Perhaps you should try some spelling variations:
petriiov » petrov (Expand Search), peteriiov (Expand Search), petriiiov (Expand Search), petruiiov (Expand Search)
petro » petrov (Expand Search), petri (Expand Search), petru (Expand Search), petero (Expand Search), petrio (Expand Search), petruo (Expand Search)
peru » petru (Expand Search), per (Expand Search)
peruo » petruo (Expand Search), pero (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petruo » peteruo (Expand Search), petriuo (Expand Search), petruuo (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 petriiov) OR (((petro OR peru) OR ((petruo OR peruo) OR periuo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR petriiov) OR (((petro OR peru) OR ((petruo OR peruo) OR periuo)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR petriiov) OR (((petro OR peru) OR ((petruo OR peruo) OR periuo)) OR petr)) o.s.*.