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)
petrui » pentrui (Expand Search), petrii (Expand Search), petriui (Expand Search), petroui (Expand Search), perui (Expand Search), petri (Expand Search)
petriiv » petriiiv (Expand Search), petroiiv (Expand Search), periiv (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (Expand Search)
petrooi » petriooi (Expand Search), petroooi (Expand Search), perooi (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 ((petriiv OR periiiv) OR ((petris OR petru) OR (petr OR ((petrooi OR petrui) OR peter)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriiv OR periiiv) OR ((petris OR petru) OR (petr OR ((petrooi OR petrui) OR peter)))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriiv OR periiiv) OR ((petris OR petru) OR (petr OR ((petrooi OR petrui) OR peter)))) o.s.*.