(1978). Coal: The other energy [kasetvideo]. Washington, D C : National Audio Visual Center.
Cita Chicago (17th ed.)Coal: The Other Energy [kasetvideo]. Washington, D C : National Audio Visual Center, 1978.
Cita MLA (9th ed.)Coal: The Other Energy [kasetvideo]. Washington, D C : National Audio Visual Center, 1978.
Atenció: Aquestes cites poden no estar 100% correctes.