1. Becker, E.W., Bley, P, Ehrfeld, U. and Ehrfeld, W., "The Separation Nozzle — An Aerodynamic Device for Large-Scale Enrichment of Uranium- 235", Rarefied Gas Dynamics, Progress in Astronautics and Aeronautics, Vol. 51, Part I, edited by J.L. Potter, AIAA, New York (1977), pp. 3–16.
2. Chatwani, A.U., Fiebig, M. Mitra, N.K. and Ehrfeld, W., "Nonequilibrium Effects and Their Modeling in Separation Nozzle", Rarefied Gas Dynamics, Progress in Astronautics and Aeronautics, Vol. 74, Part I, edited by Sam S. Fisher, AIAA, New York (1981), pp. 517 – 540.
3. Chatwani, A.U., Fiebig, M., Mitra, N.K., Schwan, W., Bley, P., Ehrfeld, W. and Fritz, W., "Tracer Monte-Carlo Simulation for an Isotope Separation Nozzle", Rarefied Gas Dynamics, Progress in Astronautics and Aeronautics, Vol. 74, Part I, edited by Sam S. Fisher, AIAA, New York (1981), pp. 541–557.
4. Berkhahn, W., Ehrfeld, W. and Krieg, G., "Berechnung der Uranisotopenentmischung in der Trenndüse bei kleinen UF6-Molenbrüchen im Zusatzgas", KFK-Bericht 2351, Gesellschaft für Kernforschung, Karlsruhe (1976).
5. Bulgakov, A.V., Kusner, Y.S., Prikhodko, V.G. and Rebrov, A.K., "Separation of Gas Mixture Components in Interacting Flows", Rarefied Gas Dynamics, Progress in Astronautics and Aeronautics, Vol. 74, Part I, edited by Sam S. Fisher, AIAA, New York (1981), pp. 607–616.