Perhaps you should try some spelling variations:
petrov » petro (Expand Search), peterov (Expand Search), petruov (Expand Search), petroov (Expand Search)
petroov » peteroov (Expand Search), petruoov (Expand Search), petrooov (Expand Search)
petruuv » peteruuv (Expand Search), petruuuv (Expand Search), petrouuv (Expand Search)
petruio » peteruio (Expand Search), petruuio (Expand Search), petrouio (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (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 petroov) OR (petruuv OR peteriuv)) OR (petruio OR (petr OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petrov OR petroov) OR (petruuv OR peteriuv)) OR (petruio OR (petr OR petri))) o.s.*".