Perhaps you should try some spelling variations:
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petriuuuov » peteriuuuov (Expand Search), petriiuuuov (Expand Search), petruiuuuov (Expand Search)
petruio » peteruio (Expand Search), petriuio (Expand Search), petruuio (Expand Search)
petruuo » peteruuo (Expand Search), petriuuo (Expand Search), petruuuo (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 (petruov OR petriuuuov)) OR (((petruio OR petruio) OR petruuo) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR (petruov OR petriuuuov)) OR (((petruio OR petruio) OR petruuo) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR (petruov OR petriuuuov)) OR (((petruio OR petruio) OR petruuo) OR petr)) o.s.*.