Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruv » petru (Expand Search), petrov (Expand Search), peteruv (Expand Search), petriuv (Expand Search), petruuv (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (Expand Search)
petriouuo » peteriouuo (Expand Search), petriiouuo (Expand Search), petruiouuo (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search), petri (Expand Search), petro (Expand Search), petrov (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 petruv) OR (((petr OR petriouuo) OR petroi) OR per)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petruv) OR (((petr OR petriouuo) OR petroi) OR per)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petruv) OR (((petr OR petriouuo) OR petroi) OR per)) o.s.*.