1. Chu, B.-T. 1957 Brown University. Wright Air Development Centre, TN 57-213.
2. Morrison, J. A. 1956 Quart. Appl. Math. 14,153–69.
3. Hayes, W. D. & Wu, C. S. 1958 Quart. Appl. Math. 16,92.
4. Cleaver, J. W. 1959 Thesis. College of Aeronautics, Cranfield. (To be published in the College of Aeronautics Rep. series.)
5. Clarke, J. F. 1958a College of Aeronautics, Cranfield, Rep. no. 117.