-working with any implementation of Common Lisp are the ILISP package
-for Emacs at @uref{http://ilisp.cons.org} and the Common Lisp HyperSpec
-at @uref{http://www.lispworks.com/reference/HyperSpec/index.html}.
+working with any implementation of Common Lisp are the SLIME
+package@footnote{Historically, the ILISP package at
+@uref{http://ilisp.cons.org/} provided similar functionality, but it
+does not support modern SBCL versions.} for Emacs at
+@uref{http://www.common-lisp.net/project/slime} and the Common Lisp
+HyperSpec at
+@uref{http://www.lispworks.com/reference/HyperSpec/index.html}.