Perhaps you should try some spelling variations:
peri » petri (Expand Search), per (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petroiov (Expand Search)
petroou » peteroou (Expand Search), petrioou (Expand Search), petrooou (Expand Search)
petrooou » peterooou (Expand Search), petriooou (Expand Search), petroooou (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petriui » peteriui (Expand Search), petriiui (Expand Search), petroiui (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 ((((petroou OR petrooou) OR petru) OR (peri OR petriui)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petriov OR ((((petroou OR petrooou) OR petru) OR (peri OR petriui)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petriov OR ((((petroou OR petrooou) OR petru) OR (peri OR petriui)) OR petr)) o.s.*.