Interesting study by Wikimedia Foundation into the availability of Wikipedia's references across different subjects. Sad to see that Chemistry ranks very low, with a high percentage of pay-walled references.
https://wikimediafoundation.org/2018/08/20/how-many-wikipedia-references-are-available-to-read/
Should also link to the twitter thread: https://twitter.com/Wikimedia/status/1031581857035497472
Inorganic and physical chemistry research student out of Uppsala, Sweden.