Plasma norepinephrine levels, vagal tone index, and flexor reflex threshold in premature neonates receiving intravenous morphine during the postoperative period: a pilot study.

The Clinical journal of pain
2000
https://researcherprofiles.org/profile/1419966
10870721
Franck LS, Boyce WT, Gregory GA, Jemerin J, Levine J, Miaskowski C