Council, National Research; Studies, Division on Earth and Life; Resources, Board on Agriculture and Natural; Animals, Committee on Minerals and Toxic Substances in Diets and Water for (2006).
Truy cập ngày 15 tháng 1 năm 2017.  ^ Council, National Research; Studies, Division on Earth and Life; Resources, Board on Agriculture and Natural; Animals, Committee on Minerals and Toxic Substances in Diets and Water for (2006).