no. 2
On 𝔭-equations and normal extensions of finite 𝔭-type. (II) The analogy of the Riemann’s problem
Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche, Série 3, Tome 18 (1964) no. 2, pp. 187-200 
@article{ASNSP_1964_3_18_2_187_0,
     author = {Morikawa, Hisasi},
     title = {On $\mathfrak {p}$-equations and normal extensions of finite $\mathfrak {p}$-type. {(II)} {The} analogy of the {Riemann{\textquoteright}s} problem},
     journal = {Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche},
     pages = {187--200},
     year = {1964},
     publisher = {Scuola normale superiore},
     volume = {Ser. 3, 18},
     number = {2},
     mrnumber = {169850},
     zbl = {0132.02601},
     language = {en},
     url = {https://www.numdam.org/item/ASNSP_1964_3_18_2_187_0/}
}
TY  - JOUR
AU  - Morikawa, Hisasi
TI  - On $\mathfrak {p}$-equations and normal extensions of finite $\mathfrak {p}$-type. (II) The analogy of the Riemann’s problem
JO  - Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche
PY  - 1964
SP  - 187
EP  - 200
VL  - 18
IS  - 2
PB  - Scuola normale superiore
UR  - https://www.numdam.org/item/ASNSP_1964_3_18_2_187_0/
LA  - en
ID  - ASNSP_1964_3_18_2_187_0
ER  - 
%0 Journal Article
%A Morikawa, Hisasi
%T On $\mathfrak {p}$-equations and normal extensions of finite $\mathfrak {p}$-type. (II) The analogy of the Riemann’s problem
%J Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche
%D 1964
%P 187-200
%V 18
%N 2
%I Scuola normale superiore
%U https://www.numdam.org/item/ASNSP_1964_3_18_2_187_0/
%G en
%F ASNSP_1964_3_18_2_187_0
Morikawa, Hisasi. On $\mathfrak {p}$-equations and normal extensions of finite $\mathfrak {p}$-type. (II) The analogy of the Riemann’s problem. Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche, Série 3, Tome 18 (1964) no. 2, pp. 187-200. https://www.numdam.org/item/ASNSP_1964_3_18_2_187_0/

[1] Morikawa H., On p-equations and normal extensions of finite p-type I, J. Math. Kyoto Univ. 2-3 (1963). | Zbl | MR

[2] Schlesinger L., Handbuch der Theorie der Linearen Differentialgleichengen Leipzig (1898). I, II4, II2. | JFM

[3] Witt E., Zyklische Korper and Algebren der Characteristik p von Grad pn, J. reine und angew. Math. Band 176 (1937) p. p. 126-140. | Zbl | JFM