https://aip.scitation.org/doi/pdf/10.1063/1.2817591?class=pdf (Verlagsversion)
Hennig, P., & Denk, W. (2007). Point-spread functions for backscattered imaging in the scanning electron microscope. Journal of Applied Physics, 102(12): 123101, pp. 1-8. doi:10.1063/1.2817591.