ArpaNet Maps Scanned maps of the network for twelve distinct periods from December 1969 to March 1977.
Publications on "Distributed Communications" Series Documents from Paul Baran from RAND Corporation, number of memoranda propsing a digital communications network for military us that could still function after sustaining heavy damage from an enemy attack.
The ARPAnet Brief, single page description of this aspect of Internet History.
The Evolution of ArpaNet Email Ian R. Hardy's thesis, published in 1996, examining the evolution of human communication on the ArpaNet.