Perhaps you should try some spelling variations:
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petrov » peterov (Expand Search), petruov (Expand Search), petroov (Expand Search), petro (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petroi » peteroi (Expand Search), petruoi (Expand Search), petrooi (Expand Search), petro (Expand Search), petrow (Expand Search)
peteru » peter (Expand Search), petru (Expand Search), peters (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.

• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petr OR (peteru OR petrov)) OR (((petri OR petroi) OR peteri) OR peteri)) _. s.~".
• Adding a wildcard symbol may retrieve word variants: fop ((petr OR (peteru OR petrov)) OR (((petri OR petroi) OR peteri) OR peteri)) _. s.*.