TOWNSEND, J. F. .; LUDWIG, J. C. . Floristics of Difficult Creek Natural Area Preserve: a Piedmont mafic woodland complex in Halifax County, Virginia, U.S.A. Journal of the Botanical Research Institute of Texas, [S. l.], v. 14, n. 2, p. 481–519, 2020. DOI: 10.17348/jbrit.v14.i2.1024. Disponível em: https://journals.brit.org/jbrit/article/view/1024. Acesso em: 24 apr. 2024.