1. Size and shape in ontogeny and phylogeny;Alberch;Paleobiology,1979
2. Albers , F. U. Meve 2002 Illustrated handbook of succulent plants: Asclepiadaceae Springer Berlin, Germany
3. Arroyo-Leuenberger , S. M. B. Bayer J. Bogner U. Eggli 2001 Illustrated handbook of succulent plants: Monocotyledons Springer Berlin, Germany
4. Anatomy of the vegetative organs of the sugar beet;Artschwager;Journal of Agricultural Research,1926
5. Systematic anatomy and ontogeny of the stem in Passifloraceae;Ayensu;Contributions from the United States National Herbarium,1964