Glöss, Alexia N., et al. “Freshness Indices of Roasted Coffee: Monitoring the Loss of Freshness for Single Serve Capsules and Roasted Whole Beans in Different Packaging: FH - HES”. CHIMIA, vol. 68, no. 3, Mar. 2014, p. 179, doi:10.2533/chimia.2014.179.