Carissa Romero’s medium post has a fantastic sources list at the bottom: https://medium.com/inclusion-insights/silicon-valley-s-diversity-problem-is-not-a-myth-29c549bc696b#.r50xdnyxw

And this NY Times piece about google’s implicit bias program is a good primer on the issue: http://www.nytimes.com/2014/09/25/technology/exposing-hidden-biases-at-google-to-improve-diversity.html