Genbaku Toka Butai [The Atomic Bombing Unit] (2013), by Yozo Kudo and Kaneko (金子力).
A leading source on pumpkin bombs by two specialists in the field, regarded by this research project as the most up-to-date and best account at the time of writing.
https://www.amazon.co.jp/dp/499072481X/
Kushu Tsushin, no. 18 (August 2016), Part 2 special feature: “The current state of research into pumpkin bomb impact sites.”
Developments since the 2013 publication of Genbaku Toka Butai.
https://www.amazon.co.jp/dp/B01JRN2X1E/
Pumpkin bomb impact-site files, in Kushu Tsushin, on the website of the national liaison council of groups recording air raids and war damage.
http://kushusensai.net/空襲通信/パンプキン被弾地/
This is Yozo Kudo’s 2016 list of the coordinates of simulated atomic bomb impact sites. I added the Kitaibaraki site and plotted the locations on the following Google map:
https://www.google.com/maps/d/u/0/edit?mid=1hA0DPcydVebEZOkLERnTbbbSFSbfJMoe&usp=sharing
Film: Kono Sora no Hana: Nagaoka Hanabi Monogatari [Flowers in the Sky: The Story of Nagaoka Fireworks], directed by Nobuhiko Obayashi, released April 7, 2012.
https://www.amazon.co.jp/dp/B00I7L8IU8/
https://ja.wikipedia.org/wiki/この空の花_長岡花火物語
YouTube: “Testimony,” Episode 1, “Passing on the story of the simulated atomic bombing,” produced by Nagaoka City, September 12, 2017.
https://www.youtube.com/watch?v=mCIzN-DEHcI
The Summer of 1945: Another Wartime Tragedy—The Bomb at Sakon: The Simulated Atomic Bomb Dropped on Nagaoka. Nagaoka War Damage Museum, April 2008.
Pumpkin! Mogi Genbaku no Natsu [Pumpkin! The Summer of the Simulated Atomic Bomb], written by Hiroko Reijo and illustrated by Kazutaka Miyao.
https://www.amazon.co.jp/dp/4065163730/
U.S. Military Records: Atomic Bombing Reports—Pumpkin Bombs and Hiroshima/Nagasaki (1993), by Yoshishige Okuzumi, Tetsuo Katsura and Yozo Kudo.
https://www.amazon.co.jp/dp/4885913500/
U.S. Military Records: The Course of the Atomic Bombing—From Wendover to Hiroshima and Nagasaki (1996), by Yoshishige Okuzumi and Yozo Kudo.
https://www.amazon.co.jp/dp/4885914981/
The Atomic Bomb: Its Theory and History, Blue Backs series (1996), by Katsuya Yamada.
A very accessible explanation of how atomic bombs work and the history of their development.
https://www.amazon.co.jp/dp/B00M1ARWYO/
Air Raids on Small and Medium-Sized Cities, by Yoshishige Okuzumi, published July 1, 1988.
https://www.amazon.co.jp/dp/4385431493/
Bomb Tokyo: What U.S. Military Mission Reports Reveal, revised edition, by Yoshishige Okuzumi and Katsumoto Saotome, published June 1, 2007. The first edition was published on June 1, 1990.
https://www.amazon.co.jp/dp/4385363218/
Fieldwork: Wartime Sites in Ibaraki Prefecture—Learn, Investigate, Reflect (2010), edited by Sumio Ito.
https://www.amazon.co.jp/dp/4894880415/
The Silverplate Bombers: A History and Registry of the Enola Gay and Other B-29s Configured to Carry Atomic Bombs, by Richard H. Campbell. First published in 2005; revised in 2012.
https://www.amazon.com/dp/0786469072/
Sakuramachi, a Night of Wartime Destruction: “Matsue, It’s the Sound of Bombers!” (1998), by Matsue Shima.
Naoko Murayama’s Observations, Corroborated by U.S. Military Records (2002), by Matsue Shima.
I referred to these two books by Matsue Shima for the Otsu air raid. Abe (安部憲夫) introduced them to me.