1. "America is the Only Rich Country Without a Law on Paid Leave for New Parents."  Economist.  18 July 2019

2. Christopher J. Ruhm and Jackqueline L. Teague.  "Parental Leave Policies in Europe and North America."  NBER Working Paper No. 5065 NBER Program(s): 
Labor Studies.  March 1995

3. Francine D. Blau and Lawrence M. Kahn.  "Female Labor Supply: Why is the U.S. Falling Behind?"  NBER Working Paper No. 18702.  January 2013

4. Mary C. Daly, Joseph H. Pedtke, Nicolas Petrosky-Nadeau, and Annemarie Schweinert.  "Why Aren’t U.S. Workers Working?"  FRBSF Economic Letter. Federal Reserve Bank of San Francisco.  13 Nov 2018