@article{ASNSP_1976_4_3_2_267_0,
     author = {Hartman, Philip},
     title = {Completely monotone families of solutions of $n$-th order linear differential equations and infinitely divisible distributions},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {267--287},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 3},
     number = {2},
     year = {1976},
     mrnumber = {404760},
     zbl = {0386.34016},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1976_4_3_2_267_0/}
}