Here are links to some articles about early spay/neuter.

The benefits of early s/n 

Early Spay/Neuter 
Video for Vets   

Pediatric S/N for Breeders 

Why Vets Don’t do early s/n 

The Truth about Juvenile Spay/Neuter

Early s/n in the cat

Early Sterilization Program
Illinois Vet Bulletin    
Pediatric S/N Myth vs Fact  

Early Spay/Neuter Many Years in the Making  
Ealy Spay/Neuter in the Cat, Winn Feline Foundation
Neuter or spay--it's definitely the right way! 
Why you should spay or neuter a kitten
Early Sterilization in Dogs and Cats
Early Age Spay/Neuter Fact Sheet
Pediatric or Early Spay/Neuter, Dr Tracy Land

Clinical Studies

Aronsohn MG and Faggella AM: Surgical techniques for neutering 6- to 14week-old kittens. J Ain Vet Med Assoc 202:53, 1993, A study describing the surgical techniques and considerations for early neutering in 96 kittens.

Faggella AM all(] Aronsohn MG Anesthetic techniques too neutering 6 to 14 weekold kittens. I Ain Net Med Assoc 202:56, 1993. A study comparing four anesthetic protocols used for early neutering in kittens

Grandy IL and Dunlop Cl: Anesthesia of pups and kittens. J All) Vet Med Assoc 198:1244, 1991. An article reviewing physiology, pharmacokinetics, and anesthetics used in pediatric patients.

Houlton JEF and McGlennon NJ: Castration and physeal closure in the cat. Vet Rec 131:466, 1992. A pilot study demonstrating delayed physeal closure in two cats castrated at 28 weeks of age.

Saluted KII, Olson PN, and Bloomberg MS: Elective, gonadectomy in the dog A review. J Am Vet Med Assoc 198:1183, 1991.

A review of the physiology of puberty and the current knowledge and potential effects of gonadectomy.

Salmeri KR, Bloomberg MS, Scruggs SL, et al: Gonadectomy in immature dogs: Effects on skeletal, physical, and behavioral development. J Am Vet Med Assoc 198:1193, 1991. Results of a study investigating the developmental effects of early neutering in (logs.

Stone KA, Cantrell CC, and AAarp AIM (A an arid uterus In Sldmer D Textbook of Small Amaral Surgery. Volume 2. Philadelphia, WB Saunders Co, 1993, p 1293. Description of surgical diseases and techniques of the ovaries and uterus.

Theran P: Early-age neutering of dogs and cats. J Am Vet Med Assoc 202: 914, 1993. A review of surgical and anesthetic techniques for neutering 6- to I 14-week-old puppies and kittens.