APA

Hellman C. I., . (1956). Elements of radio. : D Van Nostrand Company, London.

Chicago

Hellman Charles I, . 1956. Elements of radio. : D Van Nostrand Company, London.

Harvard

Hellman C. I., . (1956). Elements of radio. : D Van Nostrand Company, London.

MLA

Hellman Charles I, . Elements of radio. : D Van Nostrand Company, London. 1956.