Morton, Julia F. Wild Custard Apple. New Crops. Department of Horticulture & Landscape Architecture, Purdue University: 86–88. 1999-04-02 [2008-04-18]. (原始内容存档于2008年5月9日).
Morton, Julia F. Wild Custard Apple. New Crops. Department of Horticulture & Landscape Architecture, Purdue University: 86–88. 1999-04-02 [2008-04-18]. (原始内容存档于2008年5月9日).