Thanks!<p>Looks like bingo with my first search (a google for &#x27;rrrs mailing list rational fraction float&#x27;):<p><a href="https:&#x2F;&#x2F;groups.csail.mit.edu&#x2F;mac&#x2F;ftpdir&#x2F;scheme-mail&#x2F;HTML&#x2F;rrrs-1985&#x2F;msg00016.html" rel="nofollow">https:&#x2F;&#x2F;groups.csail.mit.edu&#x2F;mac&#x2F;ftpdir&#x2F;scheme-mail&#x2F;HTML&#x2F;rrr...</a><p>I&#x27;ve loved lisp&#x27;s power since I first encountered it in the early 80s and also admired the great care put in to various aspects of Common Lisp (which is mentioned as the foundation for scheme&#x27;s number decisions). Great stuff and still very relevant.<p>:)