Dahl, P., Harkness, B., & Maurath, G. (1990). Trace-element analysis of Mayan obsidian blades from Yucatan and Campeche Provinces, Mexico. Chemical Geology. https://doi.org/10.1016/0009-2541(90)90110-S
Dahl, Peter, B Harkness, and G Maurath. 1990. “Trace-Element Analysis of Mayan Obsidian Blades from Yucatan and Campeche Provinces, Mexico”. Chemical Geology. https://doi.org/10.1016/0009-2541(90)90110-S.
Dahl, P., B. Harkness, and G. Maurath. Trace-Element Analysis of Mayan Obsidian Blades from Yucatan and Campeche Provinces, Mexico. Chemical Geology, 15 Oct. 1990, doi:10.1016/0009-2541(90)90110-S.