# Caste division(s) * as eternal, [[sb/4/2/31#purport|SB 4.2.31]] * boys trained by, [[sb/4/8/36#purport|SB 4.8.36]] * in modern society, [[sb/4/8/36#purport|SB 4.8.36]] * maintenance of, [[sb/4/8/26#purport|SB 4.8.26]] * spirit in, four kinds of, [[sb/4/8/36#purport|SB 4.8.36]] *See also:* Varṇāśrama systems; Vedic culture