F. G. P. Costa, C. Oliveira, C. Goulart, D. Figueiredo, and R. Neto, “Use of Exogenous Enzymes on Laying Hens Feeding During the Second Production Cycle”, Int. J. Poult. Sci., vol. 7, no. 4, pp. 333–338, Feb. 2008, doi: 10.3923/ijps.2008.333.338.