Perhaps you should try some spelling variations:
petruuov » petrov (Expand Search), peteruuov (Expand Search), petruuuov (Expand Search), petrouuov (Expand Search)
petruv » peteruv (Expand Search), petruuv (Expand Search), petrouv (Expand Search)
petroov » peteroov (Expand Search), petruoov (Expand Search), petrooov (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petruuui » peteruuui (Expand Search), petruuuui (Expand Search), petrouuui (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (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 ((petruv OR peteruuv) OR (((petroov OR (petri OR petruuui)) OR petruuov) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruv OR peteruuv) OR (((petroov OR (petri OR petruuui)) OR petruuov) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruv OR peteruuv) OR (((petroov OR (petri OR petruuui)) OR petruuov) OR petr)) o.s.*.