Ketchum, M. S., & Draffin, J. O. (1932). Strength of light I beams: A report of an investigation conducted by the Engineering Experiment Station, University of Illinois in coöperation with Jones and Laughlin Steel Corporation. University of Illinois.
Παραπομπή σε μορφή Chicago (17η εκδ.)Ketchum, Milo S., και Jasper Owen Draffin. Strength of Light I Beams: A Report of an Investigation Conducted by the Engineering Experiment Station, University of Illinois in Coöperation with Jones and Laughlin Steel Corporation. Urbana, Ill.: University of Illinois, 1932.
Παραπομπή σε μορφή MLA (8th εκδ.)Ketchum, Milo S., και Jasper Owen Draffin. Strength of Light I Beams: A Report of an Investigation Conducted by the Engineering Experiment Station, University of Illinois in Coöperation with Jones and Laughlin Steel Corporation. University of Illinois, 1932.