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)
petroooov » peteroooov (Expand Search), petrioooov (Expand Search), petruoooov (Expand Search)
petrou » peterou (Expand Search), petriou (Expand Search), petruou (Expand Search)
petroio » peteroio (Expand Search), petrioio (Expand Search), petruoio (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 (((petroooov OR (petrou OR peteru)) OR petroio) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petruov) OR (((petroooov OR (petrou OR peteru)) OR petroio) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petruov) OR (((petroooov OR (petrou OR peteru)) OR petroio) OR petr)) o.s.*.