TY  - BOOK
AU  - Leffingwell, Dean Widrig, Don 
TI  - Managing softwere requirements: a unified approach 
SN  - 81-7808-260-8 
U1  - 005.14 LEF  
PY  - 2002///
CY  - Pearson education asia 
PB  - Delhi 
KW  - SOFTWARE TESTING
ER  -