Vol. 1 No. 11 (Apr 1967): "The above picture is reproduced from the front page of the Boston Globe, April 27, 1967." "Please forgive the late appearance of this issue, which is in fact out of sequence" see "BY THE MERCY OF KRISHNA".
Vol. 1 No. 15 (1967): "This issue falls just after the Appearance Days of the Supreme Lord, Sri Krishna, and of our Spiritual Master, Sri Bhaktivedanta Swami" p. 4. Janmastami on 28 Aug 1967 and Prabhupada's vyasa-puja on 29 Aug 1967 [2].
No. 18 (1968): Advertised "on sale July 1st" in previous issue p. 26.
No. 19 (1968): Advertised "on sale October 1st" in previous issue p. 20.
No. 20 (1968): Advertised "on sale November 1st" in previous issue p. 29.
No. 21 (1968): Advertised "on sale December 1st" in previous issue p. 20.
vanipedia.org
Vol. 1 Parts 1–4 (1944): "1944 - February 14 - Publishes the first 'Back to Godhead' magazine on Srila Bhaktisiddhanta Sarasvati Thakura's appearance day." [1].
Vol. 1 No. 15 (1967): "This issue falls just after the Appearance Days of the Supreme Lord, Sri Krishna, and of our Spiritual Master, Sri Bhaktivedanta Swami" p. 4. Janmastami on 28 Aug 1967 and Prabhupada's vyasa-puja on 29 Aug 1967 [2].