Perhaps you should try some spelling variations:
petr » peter (Expand Search), petro (Expand Search), per (Expand Search)
petroi » peteroi (Expand Search), petrooi (Expand Search), peroi (Expand Search), petro (Expand Search), petrov (Expand Search), petrow (Expand Search)
petrioi » peterioi (Expand Search), petroioi (Expand Search), perioi (Expand Search)
petrui » peterui (Expand Search), petroui (Expand Search), perui (Expand Search), pentrui (Expand Search)
petri » peteri (Expand Search), petroi (Expand Search), peri (Expand Search)
petru » peteru (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search)
petrooi » peterooi (Expand Search), petroooi (Expand Search), perooi (Expand Search)
peteru » peter (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 ((petrui OR petri) OR petru)) 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 ((petrui OR petri) OR petru)) OR petrooi)) _. s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petr OR peteru) OR (((petroi OR petrioi) OR ((petrui OR petri) OR petru)) OR petrooi)) _. s.*.