TODARO, Michael, P and Stephen C. Smith. Economic Development. 12th ed. New York: Pearson, 2015. ISBN 13 978-0-13-340678-8.
AGHION, P. and Steven Durlauf (ed.). Handbook of Economic Growth. Vol 2A, 2B, Amsterdam: Elsevier, 2014. ISBN: 978-0-444-53546-7 .