Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petruuuov » peteruuuov (Expand Search), petruuuuov (Expand Search), petrouuuov (Expand Search)
petriio » peteriio (Expand Search), petruiio (Expand Search), petroiio (Expand Search)
petrouio » peterouio (Expand Search), petruouio (Expand Search), petroouio (Expand Search)
petroouuio » peteroouuio (Expand Search), petruoouuio (Expand Search), petrooouuio (Expand Search)
petr » peter (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 ((petruov OR petruuuov) OR ((petriio OR (petrouio OR petroouuio)) OR (petr OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR petruuuov) OR ((petriio OR (petrouio OR petroouuio)) OR (petr OR petri))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR petruuuov) OR ((petriio OR (petrouio OR petroouuio)) OR (petr OR petri))) o.s.*.