TL;DR - 50% of Online Misogyny Caused by Women [30/May/16]

Sources:

Articles:
http://www.telegraph.co.uk/technology/2016/05/26/women-are-responsible-for-half-of-online-abuse-study-finds/
https://www.theguardian.com/technology/2016/may/26/half-of-misogynistic-tweets-sent-by-women-study-finds

Demos study "Misogyny on Twitter":
http://www.demos.co.uk/files/MISOGYNY_ON_TWITTER.pdf

Demos study is 'flawed' if your hat is made of tin foil:
http://www.abc.net.au/news/2016-05-27/research-claiming-women-are-half-of-online-abusers-'flawed'/7452568
http://www.abc.net.au/news/2016-05-27/clementine-ford/7453188

Twitter analytics:
http://www.sacdesignet.com/twitter-user-statistics-the-biggest-study-yet/
http://www.beevolve.com/twitter-statistics/

PEW research:
http://www.pewinternet.org/2014/10/22/online-harassment/

Why women use sexaully aggressive language towards each other:
http://www.nytimes.com/2013/11/19/science/a-cold-war-fought-by-women.html?src=recg&_r=1&
http://onlinelibrary.wiley.com/doi/10.1002/ab.20413/abstract
https://www.sciencedaily.com/releases/1998/03/980326075743.htm
https://www.sciencedaily.com/releases/2011/02/110224121907.htm
http://thoughtcatalog.com/james-b-barnes/2014/09/new-study-proves-that-men-dont-slut-shame-rich-women-do/

The 'will be updated in two weeks' broadband commission report for the UN:
http://www.broadbandcommission.org/Documents/reports/bb-wg-gender-report2015.pdf

The terrible version is still live though if you want to go laugh at how bad it is, apparently UN women are still standing by it:
http://www.unwomen.org/~/media/headquarters/attachments/sections/library/publications/2015/cyber_violence_gender%20report.pdf