Experimental investigation of the vibration characteristics of four designs of turbine blades and of the effect produced by varying the axial spacing between nozzle blades and turbine blades., report, February 21, 1952; (https://digital.library.unt.edu/ark:/67531/metadc58958/m1/1/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .