https://www.standard.co.uk/news/london/londoners-baffled-as-black-hole-clouds-appear-above-capital-a4159181.html
Prince Charles black spider memos
https://www.documentcloud.org/documents/2080987-the-black-spider-memos-the-secret-letters-prince.html
https://www.repository.cam.ac.uk/handle/1810/248896
https://www.repository.cam.ac.uk/bitstream/handle/1810/248896/WLDoc%20%2017-9-01%201_30%20%28PM%29.pdf?sequence=4&isAllowed=y