Pretty much anything on the internet is written by random people, all of whom could be great authorities on the subject or complete crackpots.
A couple more sources on the Myth of the Flat Earth, written by random people on the internet and found by a google search:
[0] : https://www.discovery.org/v/the-flat-earth-myth/
[1] : https://jameshannam.com/flatearth.htm
[2] : https://journals.sagepub.com/doi/abs/10.1177/003172170708800...
[3] : https://wtamu.edu/~cbaird/sq/2012/12/20/why-did-so-many-peop...