"Natalie Portman says mums "work more than anyone" and admits raising her son is more intense than any role" by Georgina Littlejohn, www.mirror.co.uk. September 30, 2013.
Mary Lou Retton, David Bender (2000). “Mary Lou Retton's Gateways to Happiness: 7 Ways to a More Peaceful, More Prosperous, More Satisfying Life”, WaterBrook Press