Perhaps you should try some spelling variations:
petriiov » petrov (Expand Search), peteriiov (Expand Search), petruiiov (Expand Search), petroiiov (Expand Search)
petriov » peteriov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrio » peterio (Expand Search), petruio (Expand Search), petroio (Expand Search)
petruio » peteruio (Expand Search), petruuio (Expand Search), petrouio (Expand Search)
petruuio » peteruuio (Expand Search), petruuuio (Expand Search), petrouuio (Expand Search)
petr » peter (Expand Search), 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 ((petriov OR petriiov) OR ((petri OR (petrio OR (petruio OR petruuio))) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petriiov) OR ((petri OR (petrio OR (petruio OR petruuio))) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petriiov) OR ((petri OR (petrio OR (petruio OR petruuio))) OR petr)) o.s.*.