1. Las erupciones históricas del volcán Tungurahua;Almeida;Bol. Geol. Ecuat.,1991
2. Pyroclastic flow generated by crater-wall collapse and outpouring of the lava pool of Arenal Volcano, Costa Rica;Alvarado;Bull. Volcanol.,2002
3. Anonymous 1, undated document. AGI, “Ydea del Reyno de Quito, expediente No. 2, 126-115”, Quito's documentation section, vol. 223, sheets 27 and followings, Sevilla, Spain.
4. Anonymous 2, around 1605. Collection of unpublished documents cited in Torres de Mendoza 1868, 461–462.
5. Anonymous 3, undated document. AGI, Quito's documentation section, vol. 376, 3 sheets, Sevilla, Spain.