Sources consulted:

https://www.forbes.com/sites/briankoberlein/2016/12/12/astronomy-charlemagne-and-the-mystery-of-phantom-time/

https://www.medievalists.net/2020/04/why-phantom-time-hypothesis-wrong/

https://www.historians.org/perspectives-article/foucaults-pendulum-and-other-prophetic-texts-september-2022/

https://www.reddit.com/r/AskHistorians/comments/2mkve2/is_there_any_credibility_to_the_phantom_time/

https://www.factualamerica.com/conspiracy-critic/dark-ages-or-deleted-ages-unmasking-the-medieval-time-warp-theory

https://www.mentalfloss.com/posts/phantom-time-hypothesis-conspiracy-theory

https://www.youtube.com/watch?v=XYOzuTa0654

https://www.discovermagazine.com/the-sciences/what-is-the-truth-behind-the-controversial-phantom-time-hypothesis

https://bigthink.com/the-past/phantom-time-hypothesis/