Śaṅkara on the Yoga-sūtras. Vol.1, Samādhi : the Vivaraṇa sub-commentary to Vyāsabhāṣya on the Yoga-sūtra-s of Pantañjali Samādhi-pāda by Śaṅkarācārya. ISBN 0710008260. Published by Routledge & Kegan Paul in 1981. Publication and catalogue information, links to buy online and reader comments.