Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petruiov (Expand Search), petroiov (Expand Search), periov (Expand Search)
petroov » petrov (Expand Search), petruoov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petruo » petru (Expand Search), petro (Expand Search), petruuo (Expand Search), petrouo (Expand Search), peruo (Expand Search)
petruiu » petruuiu (Expand Search), petrouiu (Expand Search), peruiu (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petriuo » petruiuo (Expand Search), petroiuo (Expand Search), periuo (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (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 petroov) OR (petruiu OR ((petri OR (petruo OR petriuo)) OR (petr OR peter)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petroov) OR (petruiu OR ((petri OR (petruo OR petriuo)) OR (petr OR peter)))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petroov) OR (petruiu OR ((petri OR (petruo OR petriuo)) OR (petr OR peter)))) o.s.*.