His website:

http://larch-www.lcs.mit.edu:8001/~corbato

Which contains an html rendering of his turing award lecture:

http://larch-www.lcs.mit.edu:8001/~corbato/turing91/

And his seminal work on the first time-sharing system, from 1962:

http://larch-www.lcs.mit.edu:8001/~corbato/sjcc62/