Jackson, David. Enlightenment by a Single Means: Tibetan Controversies on the "Self-Sufficient White Remedy" (dkar po chig thub). Wien: Verlag der Österreichischen Akademie der Wissenschaften, 1994: 25-8.

1. The Definition (mtshan nyid; aka Path of the Perfections [phar phyin])
2. The Mahāyāna Secret Mantra (gsang sngags)
3. The Great Seal (phyag chen)

Then elsewhere, Gampopa says his teaching of Phyag chen is superior to the "three greats" (chen po gsum):

1. Great (scholastic) Madhyamaka (dbu ma chen po)
2. (Vajrayāna) Great Seal (phyag rgya chen po)
3. Great Perfection (rdzogs pa chen po)