@phdthesis{BJHTUP11_1971__0004__P0_0,
     author = {Hirsch, Francis},
     title = {Familles r\'esolvantes, g\'en\'erateurs, cog\'en\'erateurs, potentiels},
     series = {Th\`eses d'Orsay},
     year = {1971},
     publisher = {Universit\'e Paris XI Centre d'Orsay},
     number = {4},
     language = {fr},
     url = {https://www.numdam.org/item/BJHTUP11_1971__0004__P0_0/}
}