Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Archimedes:

"

This may have been an attempt at explaining the theory of contemporary Greek astronomers such as Eratosthenes that the Earth is round.[citation needed] The fluids described by Archimedes are not self-gravitating since he assumes the existence of a point towards which all things fall in order to derive the spherical shape.[citation needed]