Klaus-Dieter Mathes . 'Gos Lo tsā ba gZhon nu dpal's commentary on the Ratnagotravibhāgavyākhyā (theg pa chen po rgyud bla ma'i bstan bcos kyi 'grel bshad de kho na nyid rab tu gsal ba'i me long /), Stuttgart: Franz Steiner Verlag, 2003, book cover