On Mon, 07 Jun 2010 15:49:04 -0700, Richard Clark
wrote:

The rudimentary version can be found in HP Journal v.6 n.1-2. HP
Journal v.12 n.4 strengthens the concept with hard copy sweeps of the
reflection coefficient of a load. By HP Journal v.16 n.6, we have the
description of automatic level control. For the 45 years beyond that
last article, more refinements.

HP Journal Nov. 1970 is dedicated to all system elements going into
one box, 8620A, 8632A (with options for an external Directional
Coupler and Power Meters).

73's
Richard Clark, KB7QHC