Palm, G Former Department Structure and Function of Natural Nerve-Net , Max Planck Institute for Biological Cybernetics, Max Planck Society; Max Planck Institute for Biological Cybernetics, Max Planck Society;
https://link.springer.com/content/pdf/10.1007/BF01214414.pdf (Publisher version)
Kern, M., Nagel, R., & Palm, G. (1977). Dilations of positive operators: Construction and ergodic theory. Mathematische Zeitschrift, 156(3), 265-277. doi:10.1007/BF01214414.