Perhaps you should try some spelling variations:
petroi » petro (Expand Search), petrov (Expand Search), petrow (Expand Search), peteroi (Expand Search), petruoi (Expand Search), petrooi (Expand Search)
petruo » petru (Expand Search), petro (Expand Search), peteruo (Expand Search), petruuo (Expand Search), petrouo (Expand Search)
petrio » petro (Expand Search), peterio (Expand Search), petruio (Expand Search), petroio (Expand Search)
petris » peteris (Expand Search), petruis (Expand Search), petrois (Expand Search)
petriuo » peteriuo (Expand Search), petruiuo (Expand Search), petroiuo (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (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 (((petroi OR ((petruo OR petriuo) OR peteruo)) OR petrio) OR (petr OR petri))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop (petris OR (((petroi OR ((petruo OR petriuo) OR peteruo)) OR petrio) OR (petr OR petri))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop (petris OR (((petroi OR ((petruo OR petriuo) OR peteruo)) OR petrio) OR (petr OR petri))) o.s.*.