Perhaps you should try some spelling variations:
petrov » peterov (Expand Search), petriov (Expand Search), petruov (Expand Search)
petriuv » peteriuv (Expand Search), petriiuv (Expand Search), petruiuv (Expand Search)
petrio » peterio (Expand Search), petriio (Expand Search), petruio (Expand Search)
petriuo » peteriuo (Expand Search), petriiuo (Expand Search), petruiuo (Expand Search)
petruuo » peteruuo (Expand Search), petriuuo (Expand Search), petruuuo (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (Expand Search)

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: fop ((petrov OR petriuv) OR ((petrio OR ((petriuo OR peteruo) OR petruuo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR petriuv) OR ((petrio OR ((petriuo OR peteruo) OR petruuo)) OR petr)) o.s.*".