Perhaps you should try some spelling variations:
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search)
petrui » peterui (Expand Search), petriui (Expand Search), petruui (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 ((petriov OR petruv) OR ((((petroi OR pero) OR petrui) OR (petruuo OR petruuo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petruv) OR ((((petroi OR pero) OR petrui) OR (petruuo OR petruuo)) OR petr)) o.s.*".