Perhaps you should try some spelling variations:
peru » petru (Expand Search), per (Expand Search)
peruo » petruo (Expand Search), pero (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petrui » peterui (Expand Search), petriui (Expand Search), petruui (Expand Search)
petruo » peteruo (Expand Search), petriuo (Expand Search), petruuo (Expand Search)
petriuo » peteriuo (Expand Search), petriiuo (Expand Search), petruiuo (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 ((((petero OR peru) OR petrui) OR ((petruo OR petriuo) OR peruo)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petriov OR ((((petero OR peru) OR petrui) OR ((petruo OR petriuo) OR peruo)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petriov OR ((((petero OR peru) OR petrui) OR ((petruo OR petriuo) OR peruo)) OR petr)) o.s.*.