Preliminary Mission Study of a Single-Launch Manned Venus Flyby with Extended Apollo Hardware, MSC Internal Note No. 67-FM-25, Jack Funk and James J. Taylor, Advanced Mission Design Branch, Mission Planning and Analysis Division, NASA Manned Spacecraft Center, Houston, Texas, February 13, 1967.
URL:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740079915_1974079915.pdf
URL:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740079915_1974079915.pdf