Perhaps you should try some spelling variations:
petruv » petru (Expand Search), petrov (Expand Search), peteruv (Expand Search), petruuv (Expand Search), petrouv (Expand Search)
petruov » petrov (Expand Search), peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petruuv » peteruuv (Expand Search), petruuuv (Expand Search), petrouuv (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petroi » peteroi (Expand Search), petruoi (Expand Search), petrooi (Expand Search), petro (Expand Search), petrov (Expand Search), petrow (Expand Search)
petruoi » peteruoi (Expand Search), petruuoi (Expand Search), petrouoi (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (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 ((petruv OR petruuv) OR (petruov OR (petr OR ((petroi OR petruoi) OR petri)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruv OR petruuv) OR (petruov OR (petr OR ((petroi OR petruoi) OR petri)))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruv OR petruuv) OR (petruov OR (petr OR ((petroi OR petruoi) OR petri)))) o.s.*.