It also contains a story in which the thunder repeats the syllable "da," which inspired the final section of T.S. Eliot's The Waste Land.  
One of these texts consists of six questions put forth to Pippalapada, while another recounts how Hayagriva obtained the head of a horse.  One of them states that "the door of the True is covered with a golden disk;" that text, which consists of only eighteen verses, describes the nature of the supreme controller, (*) Ish, and is called the Isha. The final one includes a list of all the canonical ones, and is called the Muktika. Another of them contains the doctrine of neti neti, which is described by the sage Yajnavalkya. It also contains a story in which the thunder repeats the syllable "da," which inspired the final section of T.S. Eliot's The Waste Land.  For 10 points, name these sacred texts in Hinduism which consist of 108 commentaries on the Vedas.
One of these texts consists of six questions put forth to Pippalapada, while another recounts how Hayagriva obtained the head of a horse.  
{Upanishad}s