I am reading the PDF version of the Texinfo manual,
http://www.gnu.org/software/texinfo/manual/texinfo/texinfo.pdf.
In Section C.1 there is a copyright symbol,
Copyright © 2005 Free Software Foundation, Inc.
which I think should be replaced with the Texinfo command, like this:
Copyright @copyright{} 2005 Free Software Foundation, Inc.
There are other less important differences between Section 1.11 and C.1
that would be nice to synchronize, making sample.texi a conrete reference
for teaching the basics of Texinfo.
Thanks,
Arni