Yabe , Y., M. Hatori, J. Kumagai, N. Koizumi, T. Sakuma, and M. Kawamura. “Heterotopic Ossification of the Distal Portion of Biceps Femoris”. Upsala Journal of Medical Sciences, vol. 111, no. 3, July 2009, pp. 321-7, doi:10.3109/2000-1967-058.