Two more tributes to ACC
Carl Sagan wrote a tribute to ACC in 1983 which is online here:
http://planetary.org/news/2008/0318_Arthur_C_Clarke_19172008.html
Another tribute to ACC is on the Space Elevator Reference site,
with a link to a technical paper by Clarke on the subject:
http://www.spaceelevator.com/archives/2008/03/sir_arthur_c_cl_2.html
