Perhaps you should try some spelling variations:
perov » petrov (Expand Search)
petru » peteru (Expand Search), petrou (Expand Search), peru (Expand Search)
petruo » peteruo (Expand Search), petrouo (Expand Search), peruo (Expand Search)
petri » peteri (Expand Search), petroi (Expand Search), peri (Expand Search)
petruio » peteruio (Expand Search), petrouio (Expand Search), peruio (Expand Search)
petruuo » peteruuo (Expand Search), petrouuo (Expand Search), peruuo (Expand Search)
petr » peter (Expand Search), 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 (peruv OR ((((((petru OR petruo) OR petri) OR petruio) OR petruuo) OR perov) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (peruv OR ((((((petru OR petruo) OR petri) OR petruio) OR petruuo) OR perov) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (peruv OR ((((((petru OR petruo) OR petri) OR petruio) OR petruuo) OR perov) OR petr)) o.s.*.