Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), pentruov (Expand Search), peteruov (Expand Search), petrouov (Expand Search)
petrouv » petrov (Expand Search), petrovv (Expand Search), petrowv (Expand Search), peterouv (Expand Search), petroouv (Expand Search)
petriv » petris (Expand Search), petrov (Expand Search), peteriv (Expand Search), petroiv (Expand Search)
petru » pentru (Expand Search), peteru (Expand Search), petrou (Expand Search)
petrou » petro (Expand Search), petrov (Expand Search), petrow (Expand Search), peterou (Expand Search), petroou (Expand Search)
petr » peter (Expand Search), petro (Expand Search)
petri » peteri (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 (((petruov OR petrouv) OR (petriv OR (petru OR petrou))) OR ((petr OR petri) OR per)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petruov OR petrouv) OR (petriv OR (petru OR petrou))) OR ((petr OR petri) OR per)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petruov OR petrouv) OR (petriv OR (petru OR petrou))) OR ((petr OR petri) OR per)) o.s.*.