Betts, J. A.
High frequency communications / J. A. Betts. - New York : American Elsevier Pub. Co., [1967]. - 98 p. : ill. - Introductory science texts .
Shortwave radio.
High frequency communications / J. A. Betts. - New York : American Elsevier Pub. Co., [1967]. - 98 p. : ill. - Introductory science texts .
Shortwave radio.