1. Pérez-Tamayo R. La investigación interdisciplinaria ante los problemas de salud. En: Pe?rez-Tamayo R. Sísifo y Penélope. El Colegio Nacional, Méx. D.F., 1984, 150-158.
2. Bonica JJ. Preface. In: Aronoff GM (ed). Evaluation and treatment of chronic pain. Urban & Schwarzenberg, Baltimore. 1995, 3-5.
3. Némesis Médica. La expropiación de la salud. I Ilich (ed). Edit. Jo Moritz/Planeta, México, 1964, 196-197.
4. Lipton S. Current views on the management of a pain relief centre. In: Swerdlow M. The therapy of pain. 2nd ed, MTP Press Ltd, Lancaster, 1986, 69.
5. Ferrell BR, Griffith H. Cost issues related to pain management: report from the cancer pain panel of the agency for health care policy and research. J Pain Symptom Manage. 1994;9:221-235.