Perhaps you should try some spelling variations:
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petrov » petriov (Expand Search), petruov (Expand Search), petroov (Expand Search), petro (Expand Search)
petruv » petriuv (Expand Search), petruuv (Expand Search), petrouv (Expand Search), petru (Expand Search)
petriou » petriiou (Expand Search), petruiou (Expand Search), petroiou (Expand Search)
petrioi » petriioi (Expand Search), petruioi (Expand Search), petroioi (Expand Search)
peters » petersen (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 (petrov OR petruv)) OR (petriou OR ((petrioi OR peters) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petr OR (petrov OR petruv)) OR (petriou OR ((petrioi OR peters) OR peter))) o.s.*".