http://www.nlm.nih.gov/LECTURES.dir/internet_course.dir/tcp_osi.html
(Einblicke ins Internet, 10/1995)
Layered Protocol Structures: TCP/IP vs. ISO/OSI
R. P. C. Rodgers, Lister Hill Center, NLM (May 1994)
http://www.nlm.nih.gov/LECTURES.dir/internet_course.dir/tcp_osi.html (Einblicke ins Internet, 10/1995)