no. 2
Perfect systems
Compositio Mathematica, Tome 19 (1968) no. 2, pp. 95-166. 
@article{CM_1968__19_2_95_0,
     author = {Mahler, K.},
     title = {Perfect systems},
     journal = {Compositio Mathematica},
     pages = {95--166},
     publisher = {P. Noordhoff N. V., Groningen},
     volume = {19},
     number = {2},
     year = {1968},
     mrnumber = {239099},
     zbl = {0168.31303},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1968__19_2_95_0/}
}
TY  - JOUR
AU  - Mahler, K.
TI  - Perfect systems
JO  - Compositio Mathematica
PY  - 1968
SP  - 95
EP  - 166
VL  - 19
IS  - 2
PB  - P. Noordhoff N. V., Groningen
UR  - http://archive.numdam.org/item/CM_1968__19_2_95_0/
LA  - en
ID  - CM_1968__19_2_95_0
ER  - 
%0 Journal Article
%A Mahler, K.
%T Perfect systems
%J Compositio Mathematica
%D 1968
%P 95-166
%V 19
%N 2
%I P. Noordhoff N. V., Groningen
%U http://archive.numdam.org/item/CM_1968__19_2_95_0/
%G en
%F CM_1968__19_2_95_0
Mahler, K. Perfect systems. Compositio Mathematica, Tome 19 (1968) no. 2, pp. 95-166. http://archive.numdam.org/item/CM_1968__19_2_95_0/

Coates, J.K. Nederl. Ak. Wetensch., Ser. A., Vol. 69, 421-461 (1966). | MR | Zbl

Hermite, Ch. Oeuvres, tome III, 146-149. (1873a) Oeuvres, tome III, 150-181 (1873b). Oeuvres, tome IV, 357-377 (1893).

Jager, H. K. Nederl. Ak. Wetensch., Ser. A, Vol. 67, 192-249 (1964).

Mahler, K. Math. Annalen, 105, 267-276 (1931). J. reine angew. Math., 166, 118-150 (1933) | MR | Zbl

Shidlovski, A. B. Izv. Akad. Nauk SSSR, ser. mat., 23, 35-66 (1959) Izv. Akad. Nauk SSSR, ser. mat., 26, 877-910 (1962). | MR