NASA technical notes. D-111. Fatigue strengths of aircraft materials: Axial-load fatigue tests on edgenotched sheet specimens of 2024-T3 and 7075-T6 aluminum alloys and of SAE 4130 steel with notch radii of 0.004 and 0.070 inch [with list of references]; by H. J. Grover, W. S. Hyler, and L. R. Jackson.