Perhaps you should try some spelling variations:
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petriuo » peteriuo (Expand Search), petriiuo (Expand Search), petruiuo (Expand Search)
petrio » peterio (Expand Search), petriio (Expand Search), petruio (Expand Search)
petriiiio » peteriiiio (Expand Search), petriiiiio (Expand Search), petruiiiio (Expand Search)
petriiuio » peteriiuio (Expand Search), petriiiuio (Expand Search), petruiiuio (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 peterov) OR ((petriuo OR ((petrio OR petriiiio) OR petriiuio)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR peterov) OR ((petriuo OR ((petrio OR petriiiio) OR petriiuio)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR peterov) OR ((petriuo OR ((petrio OR petriiiio) OR petriiuio)) OR petr)) o.s.*.