Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petruov » petrov (Expand Search), petriuov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
peris » petris (Expand Search), paris (Expand Search)
petruuuov » petriuuuov (Expand Search), petruuuuov (Expand Search), petrouuuov (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petruui » petriuui (Expand Search), petruuui (Expand Search), petrouui (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 ((petriov OR (petruov OR petruuuov)) OR (peris OR ((petr OR petruui) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR (petruov OR petruuuov)) OR (peris OR ((petr OR petruui) OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR (petruov OR petruuuov)) OR (peris OR ((petr OR petruui) OR peter))) o.s.*.