https://decipherment.wordpress.com/2016/03/11/classic-collaterals/

https://www.scribd.com/document/87375468/Dieseldorf-Collection-Ceramic-Corpus-of-the-Maya-Terminal-Classic-Originating-from-Molds

http://lal.tulane.edu/sites/default/files/lal/docs/Collection%20212%20Guide.pdf

Kunst und Religion der Mayavölker: Im Alten und Heutigen Mittelamerika

Explanatory notes to the lecture on the "Mayan intercalary systems" of the calendar, to be given 3rd August 1934 at 11 a.m. at University College1934

Mexican and Central American Antiquities, Calendar System and History (Smithsonian Institution / Bureau of Ethnology, Bulletin No. 28)