May 1977, pp. 337-343.
[RFC1952] Deutsch P., "GZIP file format specification version 4.3",
-Internet RFC 1952, May 1996, <http://www.ietf.org/rfc/rfc1952.txt>.
+Internet RFC 1952, May 1996, <https://www.ietf.org/rfc/rfc1952.txt>.
APPNOTE.TXT documentation file in PKZIP 1.93a (October 1991). This
version no longer seems to be available online; the latest version is
-in <http://www.pkware.com/documents/casestudies/APPNOTE.TXT>.
+in <https://www.pkware.com/documents/casestudies/APPNOTE.TXT>.