B. J. Slotman, J. H. Kralendonk, G. B. Snow, R. M. Tiwari, and A. B. M. F. Karim, “Surgery and Postoperative Radiotherapy and Radiotherapy Alone in T3-T4 Cancers of the Pyriform Sinus: Treatment results and patterns of failure”, AO, vol. 33, no. 1, pp. 55–60, Jan. 1994.