http://www.rain-tree.com/references.htm (400+ references)
http://www.herbalgram.org/catalog/reviews/centam/arvigo.html (Wade Davis review of Sastun, from http://www.herbalgram.org/directory.html (American Botanical Council site)
AUTHOR Arvigo, Rosita. TITLE Sastun : my apprenticeship with a Maya healer / Rosita Arvigo with Nadine Epstein and Marilyn Yaquinto. PUBLISHER San Francisco : HarperSanFrancisco, c1994. SUBJECT Mayas -- Ethnobotany. Mayas -- Medicine. Traditional medicine -- Belize -- Cayo District. Ethnobotany -- Belize -- Cayo District. Healers -- Belize -- Cayo District. Medicinal plants -- Belize -- Cayo District. Leyburn Library F1435.3.E74 A79 1994
http://www1.iastate.edu/~rjsalvad/gmthesis.html (full text of Utilization of Medicinal Plant Species in the Zapotec Community of Yatzachi el Bajo, Oaxaca, Mexico. [Gina Marie McAndrews, Iowa State MS 1995]
http://www.HispanicHerbs.com/ California School of Traditional Hispanic Herbalism
ref from USDA bibliography:
Ethnobotanical inventory of medicinal plants used by the Guaymi indians in western Panama. II. Joly, L.G.; Guerra, S.; Septimo, R.; Solis, P.N.; Correa A, M.D.; Gupta, M.P.; Levy, S.; Sandberg, F.; Perera, P. Limerick : Elsevier Scientific Publishers; 1990 Feb. Journal of ethno-pharmacology v. 28 (2): p. 191-206; 1990 Feb. Includes references.and a Panamanian contact, as of 1997 anyway: Prof. Mahabir P. Gupta Coordinador Internacional, Quimica Fina Farmaceutica CYTED Universidad de Panama, Apartado 10767 Panama REPUBLICA DE PANAMA Phone: +507 269 76 54 FAX:. +507 264 07 89 e-mail: gupta@pananet.com or mgupta@ancon.up.ac.pa
(National Cancer Institute has a program via U. Panama) See CIFLOR and their publications and Farmacia department page
and there's this book:
Morton, J. F. 1981. Atlas of Medicinal
Plants of Middle America. Illinois: Charles C. Thomas