Thank you to John Taber and Michael Witzel.

Would anyone have a pdf of these articles
1.
Wilhelm Halbfass, ed., Philology and Confrontation: Paul Hacker on Traditional and Modern Vedānta. SUNY Press, 1995.

2. 
Mayeda, S. On Śaṅkara's Authorship of the Kenopaniṣadbhāṣya. Indo-Iranian Journal 10, 1967, 33-55.
3. 

---,  The authenticity of the Bhagavadgītābhāṣya ascribed to Śaṅkara. Wiener Zeitschrift für die Kunde Süd- und Ostasiens. 9 (1965) 155 — 197.