F. Condi Godoi, R. Balloni Rabelo, F. Cruz Vasconcellos, M. Masumi Beppu, Preparation of Copper Nanoparticles in Chitosan Membranes and Their Application for Irreversible Humidity Indicator, Chemical Engineering Transactions. 24 (2011) 217-222. doi:10.3303/CET1124037.