Specification 93
editor, Alan Williams
Emap Architecture, 1993
 Buku Referensi
Brown, T. Merritt
Specification and uses of econometric models
Macmillan, 1970
 Buku Teks
Specification 93 clauses
editor, Alan Williams
Emap, 1993
 Buku Referensi
Specification 93 Technical
edited by Alan Williams
Emap, 1993
 Buku Referensi
Willis, Claire
Abstraction and specification with modula-2
Pitman, 1992
 Buku Teks SO