Perhaps you should try some spelling variations:
petruov » petrov (Expand Search), peteruov (Expand Search), petruuov (Expand Search), petrouov (Expand Search)
petra » petru (Expand Search), petro (Expand Search), petre (Expand Search), petera (Expand Search), petrua (Expand Search), petroa (Expand Search)
petroua » petrowna (Expand Search), peteroua (Expand Search), petruoua (Expand Search), petrooua (Expand Search)
petera » peter (Expand Search), peters (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 ((petruov OR ((petra OR ((petroua OR peteruua) OR petera)) OR petr)) OR petri) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petruov OR ((petra OR ((petroua OR peteruua) OR petera)) OR petr)) OR petri) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petruov OR ((petra OR ((petroua OR peteruua) OR petera)) OR petr)) OR petri) o.s.*.