Perhaps you should try some spelling variations:
petruuov » petrov (Expand Search), peteruuov (Expand Search), petriuuov (Expand Search), petrouuov (Expand Search)
peri » petri (Expand Search), per (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petroiov (Expand Search)
petriv » peteriv (Expand Search), petriiv (Expand Search), petroiv (Expand Search)
petrio » peterio (Expand Search), petriio (Expand Search), petroio (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petr » peter (Expand Search), petri (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 ((petriov OR (petruuov OR petriv)) OR ((((petrio OR petrio) OR petru) OR peri) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR (petruuov OR petriv)) OR ((((petrio OR petrio) OR petru) OR peri) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR (petruuov OR petriv)) OR ((((petrio OR petrio) OR petru) OR peri) OR petr)) o.s.*.