Perhaps you should try some spelling variations:
petrov » peterov (Expand Search), petriov (Expand Search), petruov (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petriuv » peteriuv (Expand Search), petriiuv (Expand Search), petruiuv (Expand Search)
petriuuio » peteriuuio (Expand Search), petriiuuio (Expand Search), petruiuuio (Expand Search)
petrui » peterui (Expand Search), petriui (Expand Search), petruui (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 (petruv OR petriuv)) OR (((petero OR petriuuio) OR petrui) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR (petruv OR petriuv)) OR (((petero OR petriuuio) OR petrui) OR petr)) o.s.*".