Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), pentruov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
petruv » petrov (Expand Search), pentruv (Expand Search), petrouv (Expand Search), peruv (Expand Search)
petru » pentru (Expand Search), petrou (Expand Search), peru (Expand Search)
petruio » pentruio (Expand Search), petrouio (Expand Search), peruio (Expand Search)
petruuo » pentruuo (Expand Search), petrouuo (Expand Search), peruuo (Expand Search)
petri » petroi (Expand Search), peri (Expand Search)
petr » petro (Expand Search), per (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 petruv) OR ((((petri OR petru) OR petruio) OR petruuo) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR petruv) OR ((((petri OR petru) OR petruio) OR petruuo) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR petruv) OR ((((petri OR petru) OR petruio) OR petruuo) OR (petr OR peter))) o.s.*.