Ballesfin, E. R. (1973). An approach to the teaching of electromagnetic forces.
Cita Chicago (17th ed.)Ballesfin, Elpha R. An Approach to the Teaching of Electromagnetic Forces. 1973.
Cita MLA (9th ed.)Ballesfin, Elpha R. An Approach to the Teaching of Electromagnetic Forces. 1973.
Atenció: Aquestes cites poden no estar 100% correctes.