1. Hougas, R. W., et al. 1958. Inventory of tuber-bearing Solanum species. Univ. of Wisc. Agr. Expt. Sta. Bull. 533 40pp. [Revised 1965; Suppl. 1966].
2. Maerz, A. and M. Rea Paul. 1950. A dictionary of color. 2nd edition. McGraw-Hill Book Co., Inc., New York.