Glossary of "Plant Systematics (1st ed.)" by Simpson (2006)
- Wood derived from a nonmonocotyledonous angiosperm, generally (but not always) harder than a softwood because of a greater concentration of fiber cells.
Glossary of "Anatomy of Seed Plants (2nd ed.)" by Esau (1977)
- Esau, K. 1977. Anatomy of Seed Plants, 2nd ed. xx + 550 pp. John Wiley & Sons, Inc., New York.
- Simpson, M. G. 2006. Plant Systematics. -xi + 590 pp. Elsevier Academic Press, Oxford.