Rayan, G.; Galal, A.; Fathi, M.; El-Attar, A. Impact of Layer Breeder Flock Age and Strain on Mechanical and Ultrastructural Properties of Eggshell in Chicken. Int. J. Poult. Sci. 2010, 9 (2), 139–147. https://doi.org/10.3923/ijps.2010.139.147.