Add some articles about bias in reviews

These may be useful for thinking through where open source projects
have room to improve in inclusion.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Change-Id: I40e5355372c8f73dbaefd681ace1b80f90b490a4

index.md

diff --git a/index.md b/index.md
index 9a707e7..d3dda14 100644
--- a/index.md
+++ b/index.md
@@ -65,6 +65,18 @@
 - Joan C. Williams in Harvard Business Review on [Hacking Tech's
   Diversity
   Problem](https://hbr.org/2014/10/hacking-techs-diversity-problem)
+- Josh Terrell et al, [Gender differences and bias in open source:
+  pull request acceptance of women versus
+  men](https://peerj.com/articles/cs-111/)
+- Nasif Imtiaz et al, [Investigating the Effects of Gender Bias on
+  GitHub](https://ieeexplore.ieee.org/abstract/document/8812110)
+  ([download](https://research.google/pubs/pub47860/))
+- Jeffrey H. Greenhaus et al, [Effects of Race on Organizational
+  Experiences, Job Performance Evaluations, and Career
+  Outcomes](https://www.jstor.org/stable/256352)
+- The Guardian's Julia Carrie Wong on [Facebook considering and
+  rejecting anonymized
+  reviews](https://www.theguardian.com/technology/2017/may/02/facebook-gender-bias-female-engineers-code)
 
 Books: