TY  - BOOK
AU  -  Ratcliff, bryan 
TI  - Introducing specification using z:a practical case study approach / Bryan Ratcliff
SN  - 0077079655
U1  - 005.12 RAT 
CY  -  London ; New York : mcgraw-Hill, c1994. 
KW  -  Z(computer program language)
ER  -