Vitanov, Nikolay K. Max Planck Institute for the Physics of Complex Systems, Max Planck Society;
https://www.researchgate.net/profile/Nikolay_Vitanov/publication/295849505_Box_model_of_migration_channels/links/57154c0a08ae8ab56695aad0.pdf (Verlagsversion)
Vitanov, N. K., & Vitanov, K. N. (2016). Box model of migration channels. Mathematical Social Sciences, 80, 108-114. doi:10.1016/j.mathsocsci.2016.02.001.