saraha's "dohas" (songs or poems in rhyming couplets) are the earliest mahamudra literature extant, and promote some of the unique features of mahamudra such as the importance of pointing-out instruction by a guru, the non-dual nature of mind, and the negation of conventional means of achieving enlightenment such as samatha-vipasyana meditation, monasticism, rituals, tantric practices and doctrinal study in favor of mahamudra 'non-meditation' and 'non-action'. later indian masters such as padmavajra, tilopa, and gampopa incorporated mahamudra into tantric, monastic and traditional meditative frameworks.