Perhaps you should try some spelling variations:
petri » peteri (Expand Search), petroi (Expand Search), peri (Expand Search)
petr » peter (Expand Search), petro (Expand Search), per (Expand Search)
petru » peteru (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search)
petrou » peterou (Expand Search), petroou (Expand Search), perou (Expand Search), petro (Expand Search), petrov (Expand Search), petrow (Expand Search)
petroou » peteroou (Expand Search), petrooou (Expand Search), peroou (Expand Search)
petruov » peteruov (Expand Search), petrouov (Expand Search), peruov (Expand Search), pentruov (Expand Search), petrov (Expand Search)
peterov » petrov (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 (petri OR (((petr OR (petru OR (petrou OR petroou))) OR (petruov OR peterov)) OR petri)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petri OR (((petr OR (petru OR (petrou OR petroou))) OR (petruov OR peterov)) OR petri)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petri OR (((petr OR (petru OR (petrou OR petroou))) OR (petruov OR peterov)) OR petri)) o.s.*.