E. E.  Gaertner, ?The history and use of milkweed (Asclepias syriaca L.)?, Econ. Bot, vol. 33, no. 2, pp. 119 - 123, 1979.

M. P.  Coons, ?Relationships ofAmaranthus caudatus?, Econ. Bot, vol. 36, no. 2, pp. 129 - 146, 1982.

R. K.  Arora, Maheshwari, M. L., Chandel, K. P. S., and Gupta, R., ?Mano (Inula racemosa): little known aromatic plant of Lahaul Valley, India?, Econ. Bot, vol. 34, no. 2, pp. 175 - 180, 1980.