(a) From "The History of Electronic Computing," ACM History Timeline (1994)

(e) From Timeline of Computing History, IEEE Computer (1996 October)

(f) From "How did the Internet get to be such a big deal?," Timeline, Franklin, Beedle and Associates, Inc. (1998)

(n) From the Heinz Nixdorf Museum, Germany (1997)

(p) From Timeline "100 years of computer science on the head of a pin," PWS Publishing (1997)

(t) From Course Technology Timeline (1997)

(w) From "A History of Computing Technology," Second Edition, M.R. Williams (1997)