Perhaps you should try some spelling variations:
petris » petri (Expand Search), petriis (Expand Search), petrois (Expand Search)
petroi » petri (Expand Search), petro (Expand Search), petrow (Expand Search), petrioi (Expand Search), petrooi (Expand Search)
petrov » petro (Expand Search), petriov (Expand Search), petroov (Expand Search)
petru » pentru (Expand Search), petri (Expand Search), petriu (Expand Search), petrou (Expand Search)
petriiv » petriiiv (Expand Search), petroiiv (Expand Search)
petr » petri (Expand Search), petro (Expand Search)

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 petroi) OR petriiv) OR petrov) OR (petru OR ((petr OR per) OR peter))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petris OR petroi) OR petriiv) OR petrov) OR (petru OR ((petr OR per) OR peter))) o.s.*".