Fernö, Mårten, et al. “Preoperative Fine Needle Aspiration from Human Breast Cancer Is a Valuable Sampling Material for Progesterone Receptor and Cytometric Dna Analysis”. Acta Oncologica, vol. 35, no. Supp 8, Jan. 1996, pp. 19-25, doi:10.3109/02841869609098517.