1. Adriance, G. W., and F. R. Brison: Propagation of horticultural plants. New York: McGraw-Hill 1939.
2. Arber, A.: Monocotyledons, a morphologic study. London: Cambridge Univ. Press 1925.
3. Arthur, J. M., J. D. Guthrie and J. M. Newell: Some effects of artificial climates on the growth and chemical composition of plants. Amer. J. Bot. 17, 416–482 (1930).
4. Artschwager, E.: Anatomy of the potato plant, with special reference to the ontogeny of the vascular system. J. agric. Res. 14, 221–252 (1918).
5. Artschwager, E.: On the anatomy of the sweet potato root, with notes on the internal breakdown. J. agric. Res. 27, 157–166 (1924a).