8Filder IJ. The relationship of embolic homogencity, number, size, and viabality to the incidence of experimental metastasis. Eur J Cancer, 1973, 9:223.
9Liotta LA. Klcinerman J, Saidel GM. The significence of hematogenous tumor cell clumps in the metastatic process. Cancer Res, 1976,36:889.
10Raz A, Bucana C, Melellan W, et al. Distribution of membrane anionic sites on B16 melanoma variants with defering lung colonizing potential. Nature (Lond), 1980, 284 : 358.