Perhaps you should try some spelling variations:
petriuov » petrov (Expand Search), peteriuov (Expand Search), petriiuov (Expand Search), petruiuov (Expand Search)
petruov » peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petriuo » peteriuo (Expand Search), petriiuo (Expand Search), petruiuo (Expand Search)
petroi » peteroi (Expand Search), petrioi (Expand Search), petruoi (Expand Search)
petruui » peteruui (Expand Search), petriuui (Expand Search), petruuui (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petru (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 petriuov) OR peteriouov) OR ((petriuo OR (petroi OR petruui)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petruov OR petriuov) OR peteriouov) OR ((petriuo OR (petroi OR petruui)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petruov OR petriuov) OR peteriouov) OR ((petriuo OR (petroi OR petruui)) OR petr)) o.s.*.