References: The authors are responsible for the accuracy of the references. Key the references (double-spaced) at the end of the manuscript. Cite the references in text in the order of appearance. Give text citation by number in parentheses. Avoid claims of priority and allusions to uncompleted work. State new hypotheses if warranted, but clearly label them as such. Do not cite a work that has been submitted for publication, but not yet accepted as a reference until it has been officially accepted. A work that has been accepted for publication but not yet published may be cited as a reference “in press.” If there are more than three authors, name only the first three authors and then use et al. Refer to the List of Journals Indexed in Index Medicus for abbreviations of journal names, or access the list at http://www.nlm.nih.gov/tsd/serials/lji.html. References that do not conform to the Journal's formatting requirements may be returned to the author. Sample references are given below:

Journal article
1. Rand NS, Dawson JM, Julio SF, et al: In vivo macrophage recruitment by murine intervertebral disc cells. J Spinal Disord 2001; 14:339–342

Book chapter
2. Todd VR: Visual information analysis: Frame of reference for visual perception, in Frames of Reference for Pediatric Occupational Therapy. Edited by Kramer P, Hinojosa J. Philadelphia, PA, Lippincott Williams & Wilkins, 1999, pp. 205–256

Entire book
3. Kellman RM, Marentette LJ (eds): Atlas of Craniomaxillofacial Fixation. Philadelphia, PA, Lippincott Williams & Wilkins, 1999

Paper in conference proceedings or abstracts
4. Moossy J: Anatomy and pathology of the vertebrobasilar system, in Vertebrobasilar arterial occlusive disease. Medical and surgical management. Edited by Berguer R, Bauer RB. Papers from the First International Conference on Vertebrobasilar Occlusive Vascular Disease, held in Detroit, MI, November 8 & 9, 1982. New York: Raven Press, 1984:1–13

Abstract
5. Sung JH, Manivel JC: Macrophages in ischemic infarcts of human brain. (Abstract) J Neuropathol Exp Neurol 1989; 48:342

Software
6. Epi Info [computer program]. Version 6. Atlanta, GA: Centers for Disease Control and Prevention 1994

Online journals
7. Friedman SA: Preeclampsia: A review of the role of prostaglandins. Obstet Gynecol [serial online]. January 1988; 71:22-37. Available from: BRS Information Technologies, McLean, VA. Accessed December 15, 1990

Database
8. CANCERNET-PDQ [database online]. Bethesda, MD: National Cancer Institute; 1996. Updated March 29, 1996

World Wide Web
9. Gostin LO: Drug use and HIV/AIDS [JAMA HIV/AIDS Web site]. June 1, 1996. Available at: http://www.ama-assn.org/special/hiv/ethics. Accessed June 26, 1997