Ask HN: Good books/research on diversity in workplace

What are some good books/research to show serious data how diversity affects workplace dynamics? (positive or negative) Diversity tends to be propagated, at least in the UK, as the cornerstone of effective workplaces, but one of the comments yesterday referenced a 2007 article from the Boston Globe about how greater diversity leads to a 'decline in social capital' [1] in communities. My reading (not sure if it's the right one, but that's one of my conclusions) from the Happiness Hypothesis [2] is that more homogenous groups tend to make people happier and easier to organise around a common goal. Both sources go against the common narrative for diversity today in communities, but they don't write about companies. Does anyone know of any serious studies that prove/disprove the effects? [1] http://archive.boston.com/news/globe/ideas/articles/2007/08/05/the_downside_of_diversity/ [2] http://www.happinesshypothesis.com/