Perhaps you should try some spelling variations:
petro » petrov (Expand Search), petri (Expand Search), petru (Expand Search), petero (Expand Search), petrio (Expand Search), petruo (Expand Search)
peteriio » peterdi (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petrv » peterv (Expand Search), petriv (Expand Search), petruv (Expand Search)
petriio » peteriio (Expand Search), petriiio (Expand Search), petruiio (Expand Search)
petruiio » peteruiio (Expand Search), petriuiio (Expand Search), petruuiio (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 petrv) OR ((petro OR ((petriio OR peteriio) OR petruiio)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petrv) OR ((petro OR ((petriio OR peteriio) OR petruiio)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petrv) OR ((petro OR ((petriio OR peteriio) OR petruiio)) OR petr)) o.s.*.