Y. Gurbuz, S. Yasar, and M. Karaman, “Effects of Addition of the Red Pepper from 4th Harvest to Corn or Wheat Based Diets on Egg-yolk Colour and Egg Production in Laying Hens”, Int. J. Poult. Sci., vol. 2, no. 2, pp. 107–111, Feb. 2003, doi: 10.3923/ijps.2003.107.111.