Betts, D. H., Bordignon, V., Hill, J. R., Winger, Q., Westhusin, M. E., Smith, L. C., & King, W. A. (2001). Reprogramming of telomerase activity and rebuilding of telomere length in cloned cattle. The National Academy of Sciences.

Betts, Dean H., Vilceu Bordignon, Jonathan R. Hill, Quinton Winger, Mark E. Westhusin, Lawrence C. Smith, và W. Allan King. Reprogramming of Telomerase Activity and Rebuilding of Telomere Length in Cloned Cattle. The National Academy of Sciences, 2001.

Betts, Dean H., et al. Reprogramming of Telomerase Activity and Rebuilding of Telomere Length in Cloned Cattle. The National Academy of Sciences, 2001.