Bell, L.N., and Labuza, T.P. 2000. "Practical Aspects of Moisture Sorption Isotherm Measurement and Use". 2nd Edition AACC Egan Press, Egan, MN Yam, K.L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009, ISBN 978-0-470-08704-6 Massey, L K, "Permeability Properties of Plastics and Elastomers", 2003, Andrew Publishing, ISBN 978-1-884207-97-6