1. 1. Burnie, D. and Wilson, D. E. 2005. Animal, 1st ed. pp. 201–201. DK Publishing, New York.
2. 2. Carlson, C. S. and Weisbrode, S. E. 2012. Section 2. Pathology of organ system: chapter 16. bones, joints, tendons, and ligaments. pp. 920–971. In: Pathologic Basis of Veterinary Disease, 5th ed. (Zachary. J. F. and McGavin, M. D. eds.), Elsevier, Seoul.
3. 3. Clutton-Brock, J. and Wilson, D. E. 2002. Smithsonian Handbook, Mammals, 1st ed. pp. 264–264. DK Publishing, New York.
4. 4. Eriksen, E. F., Hodgson, S. F., Eastell, R., Cedel, S. L., O’Fallon, W. M. and Riggs, B. L. 1990. Cancellous bone remodeling in type I (postmenopausal) osteoporosis: quantitative assessment of rates of formation, resorption, and bone loss at tissue and cellular levels. J. Bone Miner. Res. 5: 311–319.
5. 5. Kim, N. S., You, Y. S., Kang, C. W. and Choi, I. H. 2000. The changes of osteocalcin, bone-specific alkaline phosphatase, estrogen, IGF-I, Ca2+, P and bone mineral density on osteoporosis induced by ovariectomy in rats. Korean J. Vet. Res. 40: 755–762.