Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
peru » petru (Expand Search), per (Expand Search)
petruiv » peteruiv (Expand Search), petruuiv (Expand Search), petrouiv (Expand Search)
petrouv » peterouv (Expand Search), petruouv (Expand Search), petroouv (Expand Search)
petrv » peterv (Expand Search), petruv (Expand Search), petrov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petriiio » peteriiio (Expand Search), petruiiio (Expand Search), petroiiio (Expand Search)
petr » peter (Expand Search), petru (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 ((((petruiv OR perov) OR petrouv) OR petrv) OR (((petri OR peru) OR petriiio) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petruiv OR perov) OR petrouv) OR petrv) OR (((petri OR peru) OR petriiio) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petruiv OR perov) OR petrouv) OR petrv) OR (((petri OR peru) OR petriiio) OR petr)) o.s.*.