Higgins J A, Ibrahim M S, Knauert F K, Ludwig G V, Kijek T M, Ezzell J W, Courtney B C, Henchal E A
U.S. Department of Agriculture-Agricultural Research Service, Beltsville, Maryland 20705, USA.
Ann N Y Acad Sci. 1999;894:130-48. doi: 10.1111/j.1749-6632.1999.tb08056.x.