David Van Horn wrote:
> A revised draft of SRFI 77 Preliminary Proposal for R6RS Arithmetic is
> now available from the following URL:
>
>    http://srfi.schemers.org/srfi-77/

The authors have also updated the reference implementation which is now
available at the following URL:

   http://srfi.schemers.org/srfi-77/arithmetic-reference.tar.gz