TY  - GEN
AU  - Sidman, Murray
AU  - Keller, Fred
AU  - Kennedy, Edmund
AU  - Wilson, Maurice
TI  - Teaching morse-code reception with signals weighted in frequency according to their difficulty
KW  - Depósito de Retaguarda
KW  - 0220 - Depósito de Retaguarda
UR  - https://catalogo.ispa.pt/opac/biblioteca/localizacao_doc/dr.htm
UR  - https://catalogo.ispa.pt/opac/biblioteca/localizacao_doc/dr.htm
ER  -