1. Ackroyd M. H. “Nonlinear Inelastic Stability of Flexibly Connected Plane Steel Frames ” thesis presented to the University of Colorado at Boulder Colorado in 1979 in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
2. Ackroyd M. H. and Gerstle K. H. “Strength and Stiffness of Type 2 Steel Frames ” Report prepared for American Iron and Steel Institute under Project No. 199 Department of Civil Environmental and Architectural Engineering University of Colorado Boulder Colo. July 1977.
3. Kahl T. L. “Flexibly Connected Steel Frames ” thesis presented to the University of Colorado at Boulder Colo. in 1976 in partial fulfillment of the requirements for the degree of Master of Science.
4. Matrix Analysis of Semi-Rigidly Connected Frames
5. Salmon C. G. and Johnson J. E. Steel Structures Behavior and Design Intext Educational Publishers Scranton Pa. 1971 p. 793.