netlib templates copyrights

[Stephen Sinclair <radarsat1@gmail.com>]

Hello science team,

The software I am packaging embeds dftemplates and dctemplates from netlib:

http://www.netlib.org/templates/index.html

It is clear from the context that this is code to accompany a book and
intended to be used by the readers.  However, I cannot find an
explicit copyright, either on the site or in the book.  I think it is
public domain but I do not see this written anywhere.  I think this is
possibly a common issue with netlib code, how can I proceed?  Is it
safe to put Public-Domain in debian/copyright?

regards,
Steve