Ferraro 1999, p. 130 Ferraro, Giovanni (1999). "The First Modern Definition of the Sum of a Divergent Series: An Aspect of the Rise of 20th Century Mathematics". Archive for History of Exact Sciences54: 101–135. doi10.1007/s004070050036.
Ferraro 1999, p. 118Tucciarone 1973, p. 10 Ferraro critica a explicación de Tucciarone (páx. 7) sobre como é que Hölder descubriu o resultado xeral malia que son semellantes as explicacións dos dous autores sobre o tratamento de Hölder da serie 1 − 2 + 3 − 4 + ... Ferraro, Giovanni (1999). "The First Modern Definition of the Sum of a Divergent Series: An Aspect of the Rise of 20th Century Mathematics". Archive for History of Exact Sciences54: 101–135. doi10.1007/s004070050036. Tucciarone, John (1973). "The development of the theory of summable divergent series from 1880 to 1925". Archive for History of Exact Sciences10: 1–40. doi10.1007/BF00343405.
Ferraro 1999, p. 123-128 Ferraro, Giovanni (1999). "The First Modern Definition of the Sum of a Divergent Series: An Aspect of the Rise of 20th Century Mathematics". Archive for History of Exact Sciences54: 101–135. doi10.1007/s004070050036.
Ferraro 1999, p. 120-128 Ferraro, Giovanni (1999). "The First Modern Definition of the Sum of a Divergent Series: An Aspect of the Rise of 20th Century Mathematics". Archive for History of Exact Sciences54: 101–135. doi10.1007/s004070050036.