R. Frias, A. C. Ouwehand, U.-M. Jaakkola, T. Spillmann, and M. Gueimonde, “An in vivo permeability test protocol using iohexol to reduce and refine the use of laboratory rats in intestinal damage assessment”, Scand J Lab Anim Sci, vol. 40, pp. 1–6, Nov. 2014.