@article{700899,
     title = {Differential structures},
     booktitle = {General Topology and its Relations to Modern Analysis and Algebra},
     series = {GDML\_Books},
     publisher = {Academia Publishing House of the Czechoslovak Academy of Sciences},
     address = {Praha},
     year = {1967},
     pages = {87-94},
     url = {http://dml.mathdoc.fr/item/700899}
}

Ciampa, S. Differential structures, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books,  (1967), pp. 87-94. http://gdmltest.u-ga.fr/item/700899/