+.PP
+The
+.I gzip
+file format is specified in P. Deutsch, \s-1GZIP\s0 file format
+specification version 4.3, <ftp://ftp.isi.edu/in-notes/rfc1952.txt>,
+Internet RFC 1952 (May 1996). The
+.I zip
+deflation format is specified in P. Deutsch, \s-1DEFLATE\s0 Compressed
+Data Format Specification version 1.3,
+<ftp://ftp.isi.edu/in-notes/rfc1951.txt>, Internet RFC 1951 (May 1996).