Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), petruuov (Expand Search), petrouov (Expand Search), peruov (Expand Search)
peterov » petrov (Expand Search)
peteru » petru (Expand Search), peters (Expand Search)
petrouv » petrov (Expand Search), petruouv (Expand Search), petroouv (Expand Search), perouv (Expand Search)
petruiv » petruuiv (Expand Search), petrouiv (Expand Search), peruiv (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (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 (peteru OR petruiv)) OR petrouv) OR ((petr OR peter) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petruov OR peterov) OR (peteru OR petruiv)) OR petrouv) OR ((petr OR peter) OR petri)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petruov OR peterov) OR (peteru OR petruiv)) OR petrouv) OR ((petr OR peter) OR petri)) o.s.*.