Just a small note on trāyastriṃśa (sum cu rtsa gsum pa), a region in the celestial realm of sensual/sexual desire, where the Buddha is said to have visited to give teachings to his mother. The Tibetan term sum cu rtsa gsum pa is a bit misleading. It does not seem to mean here “33rd” but rather as “a set of 33,” a celestial realm where a group of 33 celestial beings reside. It may be useful to have a list of these 33 celestial beings. Si-tu-paṇ-chen provides two different lists: one perhaps the common list, and the other from the Dran nye (i.e. Smṛtyupasthānasūtra). See his bKa’ ’gyur dkar chag (p. 33). The Klong chen chos ’byung (pp. 36ff.) offers a remarkable explanation of sum cu rtsa gsum.