Cita APA (7a ed.)
Kalckar, J., & Ulfbeck, O. (1974). On the Problem of gravitational radiation. Munksgaard.
Cita Chicago Style (17a ed.)
Kalckar, Jørgen, y Ole Ulfbeck. On the Problem of Gravitational Radiation. København: Munksgaard, 1974.
Cita MLA (9a ed.)
Kalckar, Jørgen, y Ole Ulfbeck. On the Problem of Gravitational Radiation. Munksgaard, 1974.
Precaución: Estas citas no son 100% exactas.