@article{SPHM_1992___4_A1_0,
     author = {Lutz, Robert},
     title = {Physique externe et gravitation},
     journal = {S\'eminaire de Philosophie et Math\'ematiques},
     pages = {1--24},
     publisher = {IREM Paris-Nord},
     number = {4},
     year = {1992},
     language = {fr},
     url = {http://www.numdam.org/item/SPHM_1992___4_A1_0/}
}