Perhaps you should try some spelling variations:
petr » peter (Expand Search), per (Expand Search)
petro » petero (Expand Search), pero (Expand Search)
petrov » peterov (Expand Search), perov (Expand Search)
petruoi » peteruoi (Expand Search), peruoi (Expand Search), pentruoi (Expand Search)
petrow » peterow (Expand Search), perow (Expand Search), petrowna (Expand Search)
petri » peteri (Expand Search), peri (Expand Search)
petru » peteru (Expand Search), peru (Expand Search), pentru (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 ((petr OR ((((petro OR petrov) OR petruoi) OR petrow) OR (petri OR petru))) OR peterov) _. s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petr OR ((((petro OR petrov) OR petruoi) OR petrow) OR (petri OR petru))) OR peterov) _. s.*".