Braitenberg, V Forschungsgruppe Kybernetik, Max-Planck-Institut für Biologie, Max Planck Society;
https://link.springer.com/content/pdf/10.1007/BF00235589.pdf (Publisher version)
Braitenberg, V. (1967). Patterns of projection in the visual system of the fly I: Retina-lamina projections. Experimental Brain Research, 3(3), 271-298. doi:10.1007/BF00235589.