共 8 条
[3]
KELLER FS, STUDIES INT M UNPUB
[4]
MORSE EL, 1914, SFB M LETT J, V2
[5]
Prime Samuel Irenaeus, 1875, LIFE SFB MORSE LLD, P68
[6]
The relative difficulty of Morse code alphabet characters learned by the whole method
[J].
JOURNAL OF EXPERIMENTAL PSYCHOLOGY,
1943, 33 (02)
:108-114
[7]
1915, YB WIRELESS TELEGRAP
[8]
1929, ENCY BRITANNICA, V21, P883