Here are some references. I would also get a copy of ILCA's "Hazard's
of Infant Formula" (compiled by Marsha Walker) which has more
references germane to your situation. Also read references and content
in Ruth Lawrence's "Breastfeeding: A Guide for the Medical Profession,
4th ed." Does the physician in question read? I only ask because this
information if not new. The World Health Organization phrase "If anything
can be taken by mouth, human milk is the most appropriate" comes to
mind.  Duh. (Ask for his references. His list will be much shorter. And
"standard of practice" doesn't count.)

Barlow B et al. 1974. An experimental study of acute neonatal
enterocolitis: the importance of breast milk. J Pediatr Surg 9:587-94
Berseth CL: Effect of early feeding on maturation of the preterm infant's
small intestine, J Pediatr 120:947,1992
Brown EG, Ainbender E, Sweet AY: Effect of feeding stool endotoxins:
possible relationship to necrotizing enterocolitis, Pediatr Res 10:352,
1976
Bradley M. 1986. Breastfeeding and necrotizing enterocolitis. Indiana
Med. October 1986, 859-61.
Gross SJ, Slagle TA: Feeding the Low Birthweight Infant, Clin Perinatol
20:193, 1993
Kleigman R et al. 1979. Necrotizing enterocolitis in infants fed human milk.
J Pediatr 95:450-53
Kleigman R et al. 1980 Human milk feedings and NEC J Pediatr 96:780-81
Kosloske AM. 1984. Pathogenesis and prevention of necrotizing
enterocolitis: a hypothesis based on personal observation and a review
of the literature. Pediatrics 74:1086-91
Lucas A, Colt T. 1990 Breastmilk and neonatal necrotizing enterocolitis.
Lancet 336:1519-1523
Moriarty R et al. 1979 Necrotizing enterocolitis and human milk. J Pediatr
94:295-96
Stevenson D, Graham C. Stevenson J. 1980. Neonatal necrotizing
enterocolitis: 100 new cases. Adv Pediatr 27:319-40

There are many, many more. ..

Margery Wilson, IBCLC