Perhaps you should try some spelling variations:
petr » peter (Expand Search), petri (Expand Search), petru (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search), petri (Expand Search), petro (Expand Search), petrov (Expand Search)
petrioi » peterioi (Expand Search), petriioi (Expand Search), petruioi (Expand Search)
petruui » peteruui (Expand Search), petriuui (Expand Search), petruuui (Expand Search)
petrooi » peterooi (Expand Search), petriooi (Expand Search), petruooi (Expand Search)
peteru » peter (Expand Search), petru (Expand Search), peters (Expand Search)

Try widening your search to All Fields.

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