Perhaps you should try some spelling variations:
petroov » peteroov (Expand Search), petruoov (Expand Search), petrooov (Expand Search)
petruov » peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petruuuuo » peteruuuuo (Expand Search), petruuuuuo (Expand Search), petrouuuuo (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petroi » peteroi (Expand Search), petruoi (Expand Search), petrooi (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 ((petroov OR petruov) OR (((petruuuuo OR peteruo) OR ((petri OR petroi) OR per)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petroov OR petruov) OR (((petruuuuo OR peteruo) OR ((petri OR petroi) OR per)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petroov OR petruov) OR (((petruuuuo OR peteruo) OR ((petri OR petroi) OR per)) OR petr)) o.s.*.