Perhaps you should try some spelling variations:
petro » petrov (Expand Search), petri (Expand Search), petru (Expand Search), petero (Expand Search), petrio (Expand Search), petruo (Expand Search)
peru » petru (Expand Search), per (Expand Search)
petriov » peteriov (Expand Search), petriiov (Expand Search), petruiov (Expand Search)
petriiv » peteriiv (Expand Search), petriiiv (Expand Search), petruiiv (Expand Search)
petruiiv » peteruiiv (Expand Search), petriuiiv (Expand Search), petruuiiv (Expand Search)
petrio » peterio (Expand Search), petriio (Expand Search), petruio (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 (peterv OR (petriiv OR petruiiv))) OR (((petro OR peru) OR petrio) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriov OR (peterv OR (petriiv OR petruiiv))) OR (((petro OR peru) OR petrio) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriov OR (peterv OR (petriiv OR petruiiv))) OR (((petro OR peru) OR petrio) OR petr)) o.s.*.