The Simpsons their advertising. As a promotion for "The Simpsons Movie", twelve 7-Eleven stores were transformed into Kwik-E-Marts and sold "The Simpsons" related products. These included "Buzz Cola", "Krusty-O" cereal, pink doughnuts with sprinkles, and "Squishees". In 2008 consumers around the world spent $750 million on merchandise related to "The Simpsons", with half of the amount originating from the United States. By 2009, 20th Century Fox had greatly increased merchandising efforts. On April 9, 2009, the United States Postal Service unveiled a series of five 44-cent stamps featuring Homer, Marge, Bart, Lisa and Maggie, to commemorate the show's twentieth anniversary. "The Simpsons"
The Psychology of The Simpsons editors, the interviewer noted: "Get past the goofy cover, with its illustration of Homer’s beer- and TV-saturated brain, and you find analysis aimed at both TV viewers and students of psychology." The book also received positive mention in "The Times", where Andrew Billen wrote: "I can commend "D'Oh!: The Psychology of The Simpsons" and "Reading The Sopranos", since both shows are sturdy enough to support the intellectual studies." An article at "The Simpsons Archive" also wrote positively of the work: "The connection to the show and its events is solid and psychological points are illustrated using explanatory snippets from the