Compare: Z specification language, which is the main alternative to VDM-SL.
Version: BSI/VDM.
ftp://gateway.dec.com/pub/vdmsl_standard.
["The Vienna Development Method: The Meta-Language", D. Bjorner et al eds, LNCS 61, Springer 1978].
["The VDM-SL Reference Guide", J. Dawes, Pitman 1991].
["Systematic Software Development Using VDM", C.B. Jones, P-H 1989].