Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), peteriov (Expand Search), petruiov (Expand Search), petroiov (Expand Search)
petrv » petrov (Expand Search), petru (Expand Search), petro (Expand Search), peterv (Expand Search), petruv (Expand Search)
petruiiv » peteruiiv (Expand Search), petruuiiv (Expand Search), petrouiiv (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petruo » peteruo (Expand Search), petruuo (Expand Search), petrouo (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 petruiiv) OR petrv) OR ((petr OR (petruo OR peteruiiuiuo)) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR petruiiv) OR petrv) OR ((petr OR (petruo OR peteruiiuiuo)) OR petri)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriov OR petruiiv) OR petrv) OR ((petr OR (petruo OR peteruiiuiuo)) OR petri)) o.s.*.