The code base of Netlib was written at a time when computer software was not yet considered a merchandise. Therefore, no license terms or terms of use are stated for many programs. Before the Berne Convention Implementation Act of 1988 (and the earlier Copyright Act of 1976) works without a explicite Copyright notice were public domain software. Also, most of the netlib code is work of US government employees and therefore in the public domain. While several packages therefore don't have explicite waiver/anti-copyright statements, for instance the SLATEC package has an explicite statement.