TY  - RPRT
TI  - Guidance on software maintenance 
AU  - Martin, Roger J
AU  - Osborne, Wilma M
PY  - 1983
PB  - National Bureau of Standards
CY  - Gaithersburg, MD
SN  - NBS SP 500-106
DO  - 10.6028/NBS.SP.500-106
ER  -