Romagnoli, C., Zonefrati, R., Galli, G., Aldinucci, A., Nuti, N., Martelli, F., … Brandi, M. (1969). The effect of strontium chloride on human periodontal ligament stem cells. Clinical Cases in Mineral and Bone Metabolism : The Official Journal of the Italian Society of Osteoporosis, Mineral Metabolism, and Skeletal Diseases, 14(3), 283-293. https://doi.org/10.11138/ccmbm/2017.14.3.283 (Original work published 1969)