Perhaps you should try some spelling variations:
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petruuiov » peteruuiov (Expand Search), petriuuiov (Expand Search), petruuuiov (Expand Search)
petruou » peteruou (Expand Search), petriuou (Expand Search), petruuou (Expand Search)
petriui » peteriui (Expand Search), petriiui (Expand Search), petruiui (Expand Search)
petriiui » peteriiui (Expand Search), petriiiui (Expand Search), petruiiui (Expand Search)
petrouo » peterouo (Expand Search), petriouo (Expand Search), petruouo (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 petruuiov) OR (((petruou OR (petriui OR petriiui)) OR petrouo) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR petruuiov) OR (((petruou OR (petriui OR petriiui)) OR petrouo) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR petruuiov) OR (((petruou OR (petriui OR petriiui)) OR petrouo) OR petr)) o.s.*.