Haspelmath, Martin Linguistic and Cultural Evolution, Max Planck Institute for the Science of Human History, Max Planck Society;
Haspelmath, M., & Karjus, A. (2017). Explaining asymmetries in number marking: Singulatives, pluratives, and usage frequency. Linguistics, 55(6), 1213-1235. doi:10.1515/ling-2017-0026.