NCSC-TG-010: A Guide to Understanding Security Modeling in Trusted Systems, October 1992. (Aqua Book)
You can download it from the following link: https://packetstormsecurity.com/files/download/14001/NCSC-TG-010.txt
Source: https://packetstormsecurity.com/files/14001/NCSC-TG-010.txt.html