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)
petris » peteris (Expand Search), petruis (Expand Search), petrois (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petrooi » peterooi (Expand Search), petruooi (Expand Search), petroooi (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (Expand Search)
petrouv » peterouv (Expand Search), petruouv (Expand Search), petroouv (Expand Search), petrov (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 (petri OR (petroi OR petrooi))) OR (petr OR ((peterov OR petrouv) OR petris))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petris OR (petri OR (petroi OR petrooi))) OR (petr OR ((peterov OR petrouv) OR petris))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petris OR (petri OR (petroi OR petrooi))) OR (petr OR ((peterov OR petrouv) OR petris))) o.s.*.