To teach a person to fish:
Use the search feature (top right of every page), type the word "summons" and press ENTER.
Filter the results (right side of page) by type "NWN Entry"
Your answer is the first link.
To give a person a fish:
http://layonara.com/nwn/summons
the links on that page are bad.
http://layonara.com/nwn/diety-summons is the correct one.
http://layonara.com/nwn/arcane-summons is the correct one
Fixed, thanks.