Bergholm, U., et al. “Incidence of Sporadic and Familial Medullary Thyroid Carcinoma in Sweden 1959 Through 1981: A Nationwide Study in 126 Patients”. Acta Oncologica, vol. 29, no. 1, Jan. 1990, pp. 9-15, doi:10.3109/02841869009089985.