A convexity theorem for certain groups of transformations I. I. Hirschman OriginalPaper Pages: 209 - 218
Generation of solutions of systems of partial differential equations by composition of infinitesimal Baecklund transformations Charles Loewner OriginalPaper Pages: 219 - 242
Sur les espaces de solutions d’une classe générale d’équations aux dérivées partielles A. Grothendieck OriginalPaper Pages: 243 - 280