Cita APA (7th ed.)

Spangenberg , K. R. (1948). Vacum tubes. Mc Graw -hill.

Cita Chicago (17th ed.)

Spangenberg , Karl R. Vacum Tubes. New York: Mc Graw -hill, 1948.

Cita MLA (9th ed.)

Spangenberg , Karl R. Vacum Tubes. Mc Graw -hill, 1948.