1) The Everything Chihuahua Book (2006) by Joan Hustace Walker.

2) Your Chihuahua's Life: Your Complete Guide to Raising Your Pet from Puppy to Companion (2003) by Kim Campbell Thornton.

3) Chihuahuas (1998) by Marion Mondshine, another of the TFH Publications titles distributed through petshops (TFH stands for "Tropical Fish Hobbyist" though the publisher does every conceivable pet).

4) The Guide to Owning a Chihuahua (1996) by Robert Sisco, also from TFH Publications.