Perhaps you should try some spelling variations:
peri » petri (Expand Search), per (Expand Search)
petruv » peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petruuo » peteruuo (Expand Search), petriuuo (Expand Search), petruuuo (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search)
petroov » peteroov (Expand Search), petrioov (Expand Search), petruoov (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (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 (petruv OR (((((peteruo OR petruuo) OR petroi) OR (petroov OR petriov)) OR peri) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petruv OR (((((peteruo OR petruuo) OR petroi) OR (petroov OR petriov)) OR peri) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petruv OR (((((peteruo OR petruuo) OR petroi) OR (petroov OR petriov)) OR peri) OR petr)) o.s.*.