Merkel, P. Relativistic Plasmas, Max Planck Institute for Plasma Physics, Max Planck Society;
Merkel, P., Bondeson, A., Sindoni, E., & Troyon, F. (1988). Applications of the Neumann Problem to Stellarators: Magnetic Surfaces, Coils, Free-Boundary Equilibrium, Magnetic Diagnostics. In Theory of Fusion Plasmas (pp. 25-46).