@article{KYB_1967_3_1_a2,
     author = {Havrda, Jan and Charv\'at, Franti\v{s}ek},
     title = {Quantification method of classification processes. {Concept} of structural $a$-entropy},
     journal = {Kybernetika},
     pages = {30--35},
     year = {1967},
     volume = {3},
     number = {1},
     mrnumber = {0209067},
     zbl = {0178.22401},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/KYB_1967_3_1_a2/}
}