Vanilla scheme is specified in "Revised⁷ Report on the Algorithmic Language Scheme" (R7RS, 2013); or the older R6RS (2007) or R5RS (1998). There was a 1990 IEE

Vanilla scheme is specified in "Revised⁷ Report on the Algorithmic Language Scheme" (R7RS, 2013); or the older R6RS (2007) or R5RS (1998). There was a 1990 IEEE standardization of scheme (IEEE Std 1178), and last revised in 1995. But it isn't recognized as the canonical vanilla scheme like RnRS is.