Perhaps you should try some spelling variations:
petris » petri (Expand Search), petriis (Expand Search), petrois (Expand Search), peris (Expand Search)
petruo » petro (Expand Search), petriuo (Expand Search), petrouo (Expand Search), peruo (Expand Search), pentruo (Expand Search), petrio (Expand Search)
petriuv » petriiuv (Expand Search), petroiuv (Expand Search), periuv (Expand Search)
petrouo » petriouo (Expand Search), petroouo (Expand Search), perouo (Expand Search)
petr » petri (Expand Search), petro (Expand Search), per (Expand Search)
petru » petriu (Expand Search), petrou (Expand Search), peru (Expand Search), pentru (Expand Search), petri (Expand Search)
petroiuo » petrioiuo (Expand Search), petrooiuo (Expand Search), peroiuo (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 (petriuv OR ((petris OR ((((petruo OR petrouo) OR petr) OR petru) OR petroiuo)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petriuv OR ((petris OR ((((petruo OR petrouo) OR petr) OR petru) OR petroiuo)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petriuv OR ((petris OR ((((petruo OR petrouo) OR petr) OR petru) OR petroiuo)) OR peter)) o.s.*.