no. 2
The automorphism group of the modular curve X 0 (63)
Compositio Mathematica, Tome 74 (1990) no. 2, pp. 203-208. 
@article{CM_1990__74_2_203_0,
     author = {Elkies, Noam D.},
     title = {The automorphism group of the modular curve $X_0(63)$},
     journal = {Compositio Mathematica},
     pages = {203--208},
     publisher = {Kluwer Academic Publishers},
     volume = {74},
     number = {2},
     year = {1990},
     mrnumber = {1047740},
     zbl = {0708.14016},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1990__74_2_203_0/}
}
TY  - JOUR
AU  - Elkies, Noam D.
TI  - The automorphism group of the modular curve $X_0(63)$
JO  - Compositio Mathematica
PY  - 1990
SP  - 203
EP  - 208
VL  - 74
IS  - 2
PB  - Kluwer Academic Publishers
UR  - http://archive.numdam.org/item/CM_1990__74_2_203_0/
LA  - en
ID  - CM_1990__74_2_203_0
ER  - 
%0 Journal Article
%A Elkies, Noam D.
%T The automorphism group of the modular curve $X_0(63)$
%J Compositio Mathematica
%D 1990
%P 203-208
%V 74
%N 2
%I Kluwer Academic Publishers
%U http://archive.numdam.org/item/CM_1990__74_2_203_0/
%G en
%F CM_1990__74_2_203_0
Elkies, Noam D. The automorphism group of the modular curve $X_0(63)$. Compositio Mathematica, Tome 74 (1990) no. 2, pp. 203-208. http://archive.numdam.org/item/CM_1990__74_2_203_0/

[1] Birch, B.J., Kuyk, W., ed: Modular Functions of One Variable IV, Lect. Notes Math. 476, 1975. | MR | Zbl

[2] Fricke, R.: Die elliptischen Functionen und ihre Anwendungen. Leipzig-Berlin: Teubner 1922.

[3] Kenku, M.A., Momose, F., Automorphism groups of the modular curves X0(N). Comp. Math. 65 (1988) 51-80. | Numdam | MR | Zbl

[4] Mazur, B., Swinnerton-Dyer, P., Arithmetic of Weil Curves. Inv. Math. 25 (1974) 1 - 61. | MR | Zbl

[5] Matzat, B.H., Konstruktive Galoistheorie. Lect. Notes Math. 1284, 1987. | MR | Zbl