(TXT) contents1
 (TXT) contents2
 (TXT) contents3
 (TXT) contents4
 (TXT) contents5
 (TXT) contents6
 (TXT) discard
 (TXT) index
 (TXT) intro
 (TXT) notation
 (DIR) s1
 (TXT) s1_header
 (TXT) s1_macros
 (DIR) s2
 (TXT) s2_header
 (TXT) s2_macros
 (DIR) s3
 (TXT) s3_header
 (TXT) s3_macros
 (DIR) s4
 (TXT) s4_header
 (TXT) s4_macros
 (DIR) s5
 (TXT) s5_header
 (TXT) s5_macros
 (DIR) s6
 (TXT) s6_header
 (TXT) s6_macros