K. de M. Santos, “Effect of the addition of papain enzyme on digestive parameters and palatability of extruded diets for dogs”, Braz. J. Vet. Res. Anim. Sci., vol. 54, no. 4, pp. 357–365, Dec. 2017, doi: 10.11606/issn.1678-4456.bjvras.2017.125674.