Hajkhodadadi, I. ., S. . Khalaji, and A. H. . khaltabadi farahani. “Comparison of Different Chicken Egg Parameters in Young and Old Cobb Boiler Breeders”. Scientific Journal of Animal Science, vol. 3, no. 8, Aug. 2014, pp. 213-8, http://sjournals.com/index.php/sjas/article/view/823.