References
Christen, W. G., Manson, J. E., Glynn, R. J., Gaziano, J. M., Sperduto, R. D., Buring, J. E., Hennekens, C. H. (2003) ‘A randomized trial of beta carotene and age-related cataract in US physicians’, Arch Ophthalmol., 121(3), pp. 372–378.
Christian, P., West Jr., K. P, Khatry, S. K., Katz, J., LeClerq, S., Pradhan, E. K., Shrestha, S. R. (1998) ‘Vitamin A or β-carotene supplementation reduces but does not eliminate maternal night blindness in Nepal’, The Journal of Nutrition, 128(9), pp. 1458–1463.
O’Connor, A. (2005) ‘REALLY?’, The New York Times, 3 May. Available at: www.nytimes.com/ 2005/ 05/ 03/ health/ really.html?mtrref=undefined [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] (Accessed: 30/07/ 2018).