Perhaps you should try some spelling variations:
peteriov » petrov (Expand Search)
perov » petrov (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petroiov (Expand Search)
petroio » peteroio (Expand Search), petrioio (Expand Search), petrooio (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petrooi (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 peteriov) OR ((((petroio OR petru) OR perov) OR (petroi OR petroi)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR peteriov) OR ((((petroio OR petru) OR perov) OR (petroi OR petroi)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR peteriov) OR ((((petroio OR petru) OR perov) OR (petroi OR petroi)) OR petr)) o.s.*.