Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
petroiv » petrov (Expand Search), petruoiv (Expand Search), petrooiv (Expand Search), peroiv (Expand Search)
petriu » petru (Expand Search), petris (Expand Search), petruiu (Expand Search), petroiu (Expand Search), periu (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petrio » petruio (Expand Search), petroio (Expand Search), perio (Expand Search), petris (Expand Search), petro (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 petroiv) OR (((petriu OR petr) OR ((petrio OR petri) OR peteruo)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR petroiv) OR (((petriu OR petr) OR ((petrio OR petri) OR peteruo)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR petroiv) OR (((petriu OR petr) OR ((petrio OR petri) OR peteruo)) OR peter)) o.s.*.