Explore Preliminary practices (ngöndro) Sources:Preliminary practices (ngöndro) Preliminary practices (ngöndro)This category has 5 sources. Khyentse J. 0. Not for happiness: a guide to the so-called preliminary practices. ma Sgzhung Lun. 1995. The three levels of spiritual perception: an oral commentary on The three visions (nang sum) of Ngorchen Konchog Lhundrub. grub Nchen Dkon. 2002. The three visions: fundamental teachings of the Sakya Lineage of Tibetan Buddhism. Dakpa N. 2005. Opening the door to Bön. Makransky J. 1996. Offering (mChod pa) in Tibetan Ritual Literature. :312-330.