Satya Kama Varma. 1973. "Śabdapūrvako yogah," in Śrīcārudevaśāstryabhinandanagranthaḥ
[Charudeva Shastri felicitation volume], Head of the editorial committee: Satyavrat Sastri, Delhi, p. 124-129.

Satya Kama Varma 1976: “Śabdapūrvayoga,” in Studies in Indology, New Delhi, p. 238-247

Coward 1985. The Yoga of the word (śabdapūrvayoga)”. In: Adyar Library Bulletin (Madras), 49. p. 1-13 ?

The référence of Satya kama Varma's paper may be incorrect. I think I found the volume (https://archive.org/download/Pzgc_charu-deva-shastri-felicitation-volume-1974-charu-deva-shastri-felicitation-committee-delhi/Charu%20Deva%20Shastri%20Felicitation%20Volume%2C%201974%20-%20Charu%20Deva%20Shastri%20Felicitation%20Committee%20Delhi.pdf), but the publication date differs by one year, and the article is not present, neither on the pages indicated, nor elsewhere in the volume. Perhaps there is a second volume of homage to Charudeva Shastri, but I cannot find it in his library (https://archive.org/details/@satya_vrat_shastri)