Perhaps you should try some spelling variations:
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petroou » petruoou (Expand Search), petrooou (Expand Search), peroou (Expand Search)
petrov » petruov (Expand Search), petroov (Expand Search), perov (Expand Search), petro (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petroi » petruoi (Expand Search), petrooi (Expand Search), peroi (Expand Search), petro (Expand Search), petrow (Expand Search)
petruow » petruuow (Expand Search), petrouow (Expand Search), peruow (Expand Search), petrow (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 petroou) OR (petrov OR peroov)) OR (petri OR (petroi OR petruow))) OR peter) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petr OR petroou) OR (petrov OR peroov)) OR (petri OR (petroi OR petruow))) OR peter) o.s.*".