Perhaps you should try some spelling variations:
petroi » petrovi (Expand Search), peteroi (Expand Search), peroi (Expand Search)
petroui » petrovui (Expand Search), peteroui (Expand Search), peroui (Expand Search)
petro » petrov (Expand Search), petero (Expand Search), pero (Expand Search)
petruuv » peteruuv (Expand Search), peruuv (Expand Search)
petri » peteri (Expand Search), peri (Expand Search)
petru » peteru (Expand Search), peru (Expand Search)
petr » peter (Expand Search), per (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 ((petruuv OR peteruv) OR (((petri OR petroi) OR petroui) OR ((petro OR petru) OR petr))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruuv OR peteruv) OR (((petri OR petroi) OR petroui) OR ((petro OR petru) OR petr))) o.s.*".