Perhaps you should try some spelling variations:
peterov » petrov (Expand Search)
petroov » petrov (Expand Search), peteroov (Expand Search), petruoov (Expand Search), petrooov (Expand Search)
pero » petro (Expand Search), per (Expand Search), pro (Expand Search)
peteri » peterdi (Expand Search), peter (Expand Search), peters (Expand Search)
petroui » peteroui (Expand Search), petruoui (Expand Search), petrooui (Expand Search)
petruui » peteruui (Expand Search), petruuui (Expand Search), petrouui (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 petroov) OR ((pero OR (peteri OR (petroui OR petruui))) OR (petr OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((peterov OR petroov) OR ((pero OR (peteri OR (petroui OR petruui))) OR (petr OR petri))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((peterov OR petroov) OR ((pero OR (peteri OR (petroui OR petruui))) OR (petr OR petri))) o.s.*.