Sacred Learning
Śukla Yajurveda
Vājasaneyi saṃhitā; Madhyandina and Kāṇva schools.
In the Vājasaneyi recension the Īśāvāsya Upaniṣad is the last chapter of the saṃhitā itself. That is why the Īśā slice in this library cites Śukla Yajurveda numbering.