Shri Shankarabhagavatpada's Upaniṣadbhāṣyam, vol. 1 (for the first 8 upaniṣads), with
the commentaries of Shri Anandagiriacharya for all, and in addition commentaries for
Katha, Mandukya and Taittiriya by great acharyas and Taittiriyavartika of Shri Sureshvaracharya
with commentary, edited with notes etc. by S. Subrahmanyashastri, 2004