Z. Niu, J. Fu, Y. Gao, and F. Liu, “Influence of Paprika Extract Supplement on Egg Quality of Laying Hens Fed Wheat-Based Diet”, Int. J. Poult. Sci., vol. 7, no. 9, pp. 887–889, Aug. 2008, doi: 10.3923/ijps.2008.887.889.