Jasper is reading "Tips for Surviving a Nuclear Attack". This book does not exist in real-life, although there are actually some similar ones.
Jasper says: The people of Nagasaki never saw it coming". He is referring to the atomic bombings of Hiroshima and Nagasaki, in Japan, from 6 Aug 1945 - 9 Aug 1945. The bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the only use of nuclear weapons in an armed conflict. Dr. Robert Oppenheimer developed the bomb, the story of which is told in the Oscar-winning film "Oppenheimer" (2023).
The title of this episode "Witch's Lament", comes from a song of the same name (also known as simply "Lament"), taken from the Stephen Sondheim musical, 'Into the Woods' (1987).