1. Dan Coombs (Lyondell Basell) Propylene: The “Other” Olefin: Goldman Sachs Chemical Intensity Conference 2016 https://www.lyondellbasell.com/globalassets/investors/events/2016/160314-lyb-gs-chemical-intensity-conference-final.pdf
2. World population http://en.wikipedia.org/wiki/World_population
3. Plastic Europe presentation (Resource efficiency: Best Practices for the recovery of plastics waste in Europe) http://www.plasticseurope.org/Document/Document/20100224161413