Perhaps you should try some spelling variations:
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petriu » peteriu (Expand Search), petriiu (Expand Search), petruiu (Expand Search)
petrio » peterio (Expand Search), petriio (Expand Search), petruio (Expand Search)
petroio » peteroio (Expand Search), petrioio (Expand Search), petruoio (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 ((petruov OR petriov) OR ((petriu OR peteru) OR ((petrio OR petroio) OR petr))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR petriov) OR ((petriu OR peteru) OR ((petrio OR petroio) OR petr))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR petriov) OR ((petriu OR peteru) OR ((petrio OR petroio) OR petr))) o.s.*.