Perhaps you should try some spelling variations:
petruoov » petrov (Expand Search), peteruoov (Expand Search), petruuoov (Expand Search), petrouoov (Expand Search)
petriov » peteriov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petroou » peteroou (Expand Search), petruoou (Expand Search), petrooou (Expand Search)
petrouo » peterouo (Expand Search), petruouo (Expand Search), petroouo (Expand Search)
petroiuo » peteroiuo (Expand Search), petruoiuo (Expand Search), petrooiuo (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 ((petruoov OR petriov) OR (((petri OR petroou) OR (petrouo OR petroiuo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruoov OR petriov) OR (((petri OR petroou) OR (petrouo OR petroiuo)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruoov OR petriov) OR (((petri OR petroou) OR (petrouo OR petroiuo)) OR petr)) o.s.*.