Common Lisp the Language, 2nd Edition
All numbers in this book are in decimal notation unless there is an explicit indication to the contrary. (Decimal notation is normally taken for granted, of course. Unfortunately, for certain other dialects of Lisp, MacLisp in particular, the default notation for numbers is octal (base 8) rather than decimal, and so the use of decimal notation for describing Common Lisp is, taken in its historical context, a bit unusual!)