Stephen Dole's follow-up paper which was published in Icarus a year after the original was published by the RAND corporation.
Its main usages are as a cross-reference for references found in the previous paper, its comparison of a small dataset against the available accurate (for the time) measurements of the solar system, and its slightly alternate look at some of the formula used.
The model itself seems to be identical to the one in the previous paper.
N/a - no source