Allaye-ChanA. C., WhiteR. G., HollemanD. F., and RussellD. E. “Seasonal Concentrations of Cesium-137 in Rumen Content, Skeletal Muscles and Feces of Caribou from the Porcupine Herd: Lichen Ingestion Rates and Implications for Human Consumption”. Rangifer, Vol. 10, no. 3, Sept. 1990, pp. 17-24, doi:10.7557/2.10.3.816.