Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petriuov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), petruv (Expand Search)
peterov » petrov (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petruo » petriuo (Expand Search), petruuo (Expand Search), petrouo (Expand Search), petru (Expand Search), petro (Expand Search)
petruuo » petriuuo (Expand Search), petruuuo (Expand Search), petrouuo (Expand Search)
petruiiuuo » petriuiiuuo (Expand Search), petruuiiuuo (Expand Search), petrouiiuuo (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 peterov) OR ((petr OR (petruo OR (petruuo OR petruiiuuo))) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR peterov) OR ((petr OR (petruo OR (petruuo OR petruiiuuo))) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR peterov) OR ((petr OR (petruo OR (petruuo OR petruiiuuo))) OR peter)) o.s.*.