Anand KJ, Sippell WG, Aynsley-Green A (1987). “Randomized trial of fentanyl anaesthesia in preterm babies undergoing surgery: effects on stress response”. Lancet. 1 (8524): 62–66. doi:10.1016/s0140-6736(87)91907-6. PMID2879174.
Anand KJ, Scalzo FM (2000). “Can Adverse Neonatal Experiences Alter Brain Development and Subsequent Behavior?”. Biology of the Neonate. 77 (2): 69–82. doi:10.1159/000014197.
"The immaturity of the nervous system affecting mostly inhibitors filters; a whole body of evidence now suggests that the pain would be increased, potentiated by reducing the segmental spinal cord controls." Dr Daniel Annequin, 1999 in french: L'immaturité du système nerveux touche plus particulièrement les filtres inhibiteurs; tout un faisceau d'arguments suggère maintenant que la douleur serait augmentée, potentialisée par la diminution de ces contrôles segmentaires médullaires.