Perhaps you should try some spelling variations:
petris » petri (Expand Search), petriis (Expand Search), petrois (Expand Search), peris (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), petriu (Expand Search), petrou (Expand Search), peru (Expand Search)
petruo » pentruo (Expand Search), petrio (Expand Search), petro (Expand Search), petriuo (Expand Search), petrouo (Expand Search), peruo (Expand Search)
petriu » petri (Expand Search), petriiu (Expand Search), petroiu (Expand Search), periu (Expand Search)
petriio » petriiio (Expand Search), petroiio (Expand Search), periio (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (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 (((peruov OR petris) OR petru) OR (((petruo OR petriu) OR petriio) OR (petr OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (((peruov OR petris) OR petru) OR (((petruo OR petriu) OR petriio) OR (petr OR peter))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (((peruov OR petris) OR petru) OR (((petruo OR petriu) OR petriio) OR (petr OR peter))) o.s.*.