Wireless Telegraphy and Telephony Simply Explained by Alfred Powell Morgan

Reginald Fessenden - Wikipedia

Crystal detector - Wikipedia

The Boys Book of Science and Construction by MORGAN, Alfred Powell - 1922

The Flame Audion

Alfred Powell Morgan

1914 Wireless Telegraph Construction For Amateurs by Alfred Powell Morgan

principles wireless telegraphy - AbeBooks

Wireless Telegraph Construction for Amateurs

Radio Telephony - AbeBooks