Perhaps you should try some spelling variations:
petrov » petro (Expand Search), peterov (Expand Search), petroov (Expand Search), perov (Expand Search)
petruuv » pentruuv (Expand Search), peteruuv (Expand Search), petrouuv (Expand Search), peruuv (Expand Search)
petru » pentru (Expand Search), peteru (Expand Search), petrou (Expand Search), peru (Expand Search)
petr » peter (Expand Search), petro (Expand Search), per (Expand Search)
petri » peteri (Expand Search), petroi (Expand Search), peri (Expand Search)
peteri » peterdi (Expand Search), peter (Expand Search), peters (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 petruuv) OR (petru OR (petr OR (peteri OR petri)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petrov OR petruuv) OR (petru OR (petr OR (peteri OR petri)))) o.s.*".