Perhaps you should try some spelling variations:
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrou » peterou (Expand Search), petruou (Expand Search), petroou (Expand Search), petru (Expand Search), petro (Expand Search), petrov (Expand Search)
petroi » peteroi (Expand Search), petruoi (Expand Search), petrooi (Expand Search), petro (Expand Search), petrov (Expand Search), petrow (Expand Search)
petrooi » peterooi (Expand Search), petruooi (Expand Search), petroooi (Expand Search)
peteroi » peterdi (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 petri) OR petrou) OR ((petroi OR peteroi) OR (petrooi OR peteriooi))) _. s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petr OR petri) OR petrou) OR ((petroi OR peteroi) OR (petrooi OR peteriooi))) _. s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petr OR petri) OR petrou) OR ((petroi OR peteroi) OR (petrooi OR peteriooi))) _. s.*.