Perhaps you should try some spelling variations:
petriov » petrov (Expand Search), peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruov » petrov (Expand Search), peteruov (Expand Search), petriuov (Expand Search), petruuov (Expand Search)
petrue » petru (Expand Search), petre (Expand Search), peterue (Expand Search), petriue (Expand Search), petruue (Expand Search)
petera » peter (Expand Search), peters (Expand Search), petra (Expand Search)
petruoua » peteruoua (Expand Search), petriuoua (Expand Search), petruuoua (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 (((petriov OR petruov) OR ((petrue OR (petruoua OR petera)) OR petr)) OR peterdi) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((petriov OR petruov) OR ((petrue OR (petruoua OR petera)) OR petr)) OR peterdi) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((petriov OR petruov) OR ((petrue OR (petruoua OR petera)) OR petr)) OR peterdi) o.s.*.