Perhaps you should try some spelling variations:
petr » peter (Expand Search), petri (Expand Search), petru (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search), petrov (Expand Search)
petroou » peteroou (Expand Search), petrioou (Expand Search), petruoou (Expand Search)
petrooi » peterooi (Expand Search), petriooi (Expand Search), petruooi (Expand Search)
peteru » peter (Expand Search), petru (Expand Search), peters (Expand Search)
peterow » petrow (Expand Search)
peteri » peterdi (Expand Search), peter (Expand Search), petri (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 ((petruov OR petroou) OR peterow))) OR (peteri OR petrooi)) _. s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petr OR (peteru OR ((petruov OR petroou) OR peterow))) OR (peteri OR petrooi)) _. s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petr OR (peteru OR ((petruov OR petroou) OR peterow))) OR (peteri OR petrooi)) _. s.*.