Calcul symbolique approximatif
Séminaire Schwartz, Tome 4 (1959-1960), Exposé no. 7, p. 1-6
@article{SLS_1959-1960__4__A7_0,
     author = {Malgrange, Bernard},
     title = {Calcul symbolique approximatif},
     journal = {S\'eminaire Schwartz},
     publisher = {Secr\'etariat math\'ematique},
     volume = {4},
     year = {1959-1960},
     note = {talk:7},
     pages = {1-6},
     language = {fr},
     url = {http://http://www.numdam.org/item/SLS_1959-1960__4__A7_0}
}
Malgrange, Bernard. Calcul symbolique approximatif. Séminaire Schwartz, Tome 4 (1959-1960) Exposé no. 7, pp. 1-6. http://www.numdam.org/item/SLS_1959-1960__4__A7_0/

[1] Calderón (A.P.) and Zygmund (A.). - Singular integral operators and differential equations, Amer. J. of Math., t. 79, 1957, p. 901-921. | MR 100768 | Zbl 0081.33502

[2] Mikhlin (S.G.). - Equations intégrales singulières [en russe], Uspekhi Mat. Nauk SSSR, N. S., t. 3(25), 1948, p. 29-112.