Perhaps you should try some spelling variations:
petriiov » petrov (Expand Search), peteriiov (Expand Search), petriiiov (Expand Search), petroiiov (Expand Search)
peri » petri (Expand Search), per (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petroiov (Expand Search)
petruou » peteruou (Expand Search), petriuou (Expand Search), petrouou (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petrui » peterui (Expand Search), petriui (Expand Search), petroui (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petro (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 petriiov) OR ((((petruou OR peterou) OR petru) OR (peri OR petrui)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petriiov) OR ((((petruou OR peterou) OR petru) OR (peri OR petrui)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petriiov) OR ((((petruou OR peterou) OR petru) OR (peri OR petrui)) OR petr)) o.s.*.