Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), peteriov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
peterov » petrov (Expand Search)
petruo » petru (Expand Search), petro (Expand Search), peteruo (Expand Search), petruuo (Expand Search), petrouo (Expand Search)
petriiiuo » peteriiiuo (Expand Search), petruiiiuo (Expand Search), petroiiiuo (Expand Search)
petriuuo » peteriuuo (Expand Search), petruiuuo (Expand Search), petroiuuo (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (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 peterov) OR (((petruo OR petriiiuo) OR petriuuo) OR (petr OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR peterov) OR (((petruo OR petriiiuo) OR petriuuo) OR (petr OR petri))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR peterov) OR (((petruo OR petriiiuo) OR petriuuo) OR (petr OR petri))) o.s.*.