On Siegel's zero
Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 4, Volume 2 (1975) no. 4, p. 571-583 
@article{ASNSP_1975_4_2_4_571_0,
     author = {Goldfeld, Dorian M. and Schinzel, A.},
     title = {On Siegel's zero},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 2},
     number = {4},
     year = {1975},
     pages = {571-583},
     zbl = {0327.10041},
     mrnumber = {404213},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1975_4_2_4_571_0}
}

Goldfeld, D. M.; Schinzel, A. On Siegel's zero. Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 4, Volume 2 (1975) no. 4, pp. 571-583. http://www.numdam.org/item/ASNSP_1975_4_2_4_571_0/

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