Perhaps you should try some spelling variations:
petris » petri (Expand Search), peteris (Expand Search), petriis (Expand Search), petrois (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petruoi » pentruoi (Expand Search), petrioi (Expand Search), peteruoi (Expand Search), petriuoi (Expand Search), petrouoi (Expand Search)
petroi » petri (Expand Search), petro (Expand Search), petrov (Expand Search), peteroi (Expand Search), petrioi (Expand Search), petrooi (Expand Search)
petr » peter (Expand Search), petri (Expand Search), petro (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 ((petris OR (petru OR (petroi OR petruoi))) OR (petr OR ((peterov OR petru) OR petris))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petris OR (petru OR (petroi OR petruoi))) OR (petr OR ((peterov OR petru) OR petris))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petris OR (petru OR (petroi OR petruoi))) OR (petr OR ((peterov OR petru) OR petris))) o.s.*.