Perhaps you should try some spelling variations:
petriov » peteriov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petriv » peteriv (Expand Search), petruiv (Expand Search), petroiv (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petruo » peteruo (Expand Search), petruuo (Expand Search), petrouo (Expand Search)
petruuuo » peteruuuo (Expand Search), petruuuuo (Expand Search), petrouuuo (Expand Search)
petrio » peterio (Expand Search), petruio (Expand Search), petroio (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 petriv) OR ((((petri OR (petruo OR petruuuo)) OR petero) OR petrio) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petriv) OR ((((petri OR (petruo OR petruuuo)) OR petero) OR petrio) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petriv) OR ((((petri OR (petruo OR petruuuo)) OR petero) OR petrio) OR petr)) o.s.*.