Perhaps you should try some spelling variations:
peterov » petrov (Expand Search)
petruv » petru (Expand Search), petrov (Expand Search), peteruv (Expand Search), petruuv (Expand Search), petrouv (Expand Search)
petrio » petris (Expand Search), petro (Expand Search), peterio (Expand Search), petruio (Expand Search), petroio (Expand Search)
petriuuov » peteriuuov (Expand Search), petruiuuov (Expand Search), petroiuuov (Expand Search)
petroio » peteroio (Expand Search), petruoio (Expand Search), petrooio (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 (((peterov OR petriuuov) OR petruv) OR (((petrio OR petroio) OR per) OR (petr OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((peterov OR petriuuov) OR petruv) OR (((petrio OR petroio) OR per) OR (petr OR petri))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((peterov OR petriuuov) OR petruv) OR (((petrio OR petroio) OR per) OR (petr OR petri))) o.s.*.