NCSC-TG-018: A Guide to Understanding Object Reuse in Trusted Systems, July 1992. (Light Blue Book)
You can download it from the following link: https://packetstormsecurity.com/files/download/14008/NCSC-TG-018.html
Source: https://packetstormsecurity.com/files/14008/NCSC-TG-018.html.html