Multiple-magazine bind-in cards: Two magazines
Bind-in cards are cards bound into magazines with saddle-stitch binding or perfect binding. Publishers may sell these cards to advertisers or use them to advertise their own magazine. Many magazines find bind-in one of the most cost-effective methods of gaining new subscribers. Publishers may bind in a single card or a page of cards which may be separated along perforated edges. Publishers that have several magazines often advertise related magazines on bind-in cards inserted in magazines whose audience is similar.
In this sample: Christianity Today and Leadership Journal