Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petriov » petrov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petriuuuv » petruuuv (Expand Search), petrisuuv (Expand Search), petruiuuuv (Expand Search), petroiuuuv (Expand Search)
petriu » petru (Expand Search), petris (Expand Search), petruiu (Expand Search), petroiu (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search)
petr » petru (Expand Search), petro (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 ((((petri OR petriuuuv) OR petruov) OR petriov) OR (petriu OR ((petr OR per) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petri OR petriuuuv) OR petruov) OR petriov) OR (petriu OR ((petr OR per) OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petri OR petriuuuv) OR petruov) OR petriov) OR (petriu OR ((petr OR per) OR peter))) o.s.*.