Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), petriiov (Expand Search), petruiov (Expand Search), petroiov (Expand Search), petriv (Expand Search), petrisv (Expand Search)
petruv » petru (Expand Search), petrov (Expand Search), petriuv (Expand Search), petruuv (Expand Search), petrouv (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petrio » petriio (Expand Search), petruio (Expand Search), petroio (Expand Search), petri (Expand Search), petris (Expand Search), petro (Expand Search)
petruo » petriuo (Expand Search), petruuo (Expand Search), petrouo (Expand Search), petru (Expand Search), petro (Expand Search)
petriuo » petriiuo (Expand Search), petruiuo (Expand Search), petroiuo (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 petriov) OR (((petr OR petrio) OR (petruo OR petriuo)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR petruv) OR petriov) OR (((petr OR petrio) OR (petruo OR petriuo)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriov OR petruv) OR petriov) OR (((petr OR petrio) OR (petruo OR petriuo)) OR peter)) o.s.*.