Perhaps you should try some spelling variations:
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruuv » peteruuv (Expand Search), petriuuv (Expand Search), petruuuv (Expand Search)
petriu » peteriu (Expand Search), petriiu (Expand Search), petruiu (Expand Search)
petrou » peterou (Expand Search), petriou (Expand Search), petruou (Expand Search)
petruio » peteruio (Expand Search), petriuio (Expand Search), petruuio (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 (peteroouv OR petruuv)) OR (((petriu OR petrou) OR petruio) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR (peteroouv OR petruuv)) OR (((petriu OR petrou) OR petruio) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR (peteroouv OR petruuv)) OR (((petriu OR petrou) OR petruio) OR petr)) o.s.*.