Perhaps you should try some spelling variations:
petroiov » petrov (Expand Search), peteroiov (Expand Search), petruoiov (Expand Search), petrooiov (Expand Search)
petriiov » petrov (Expand Search), peteriiov (Expand Search), petruiiov (Expand Search), petroiiov (Expand Search)
petruv » peteruv (Expand Search), petruuv (Expand Search), petrouv (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrui » peterui (Expand Search), petruui (Expand Search), petroui (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 (petroiov OR petriiov)) OR (((petri OR petrui) OR peteruooui) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruv OR (petroiov OR petriiov)) OR (((petri OR petrui) OR peteruooui) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruv OR (petroiov OR petriiov)) OR (((petri OR petrui) OR peteruooui) OR petr)) o.s.*.