NogueraE., “Exploraciones en Xochicalco”, Cuadernos Americanos, xix (1945), 119–57; Pin̅ChanR., “Descubrimiento arqueologico en Xochicalco”, Boletín del INAH, ii (1960), 1–4.
2.
Another observation regarding the a.d. 630 eclipse is that the sun and moon each passed within 5° of the zenith about 5½ hours before the eclipse and probably would have been observable in the zenith tube in the caves at Xochicalco. See AveniA. and HartungH., “The observation of the sun at the time of passage through the zenith in Mesoamerica”, Archaeoastronomy (supplement to Journal for the history of astronomy, no. 3 (1981), S51–70.
3.
AveniA. and GibbsS., “On the orientation of pre-Columbian buildings in central Mexico”, American antiquity, xli (1976), 510–17.
4.
ClossM., “Cognitive aspects of ancient Maya eclipse theory”, in World archaeoastronomy, ed. by AveniA. (Oxford, 1989), 389–415.
