@article{M2AN_1971__5_1_105_0,
     author = {Boulaye, Guy},
     title = {Notions d'extension dans les treillis},
     journal = {ESAIM: Mathematical Modelling and Numerical Analysis - Mod\'elisation Math\'ematique et Analyse Num\'erique},
     pages = {105--116},
     publisher = {Dunod},
     volume = {5},
     number = {R1},
     year = {1971},
     zbl = {0237.06004},
     mrnumber = {294186},
     language = {fr},
     url = {archive.numdam.org/item/M2AN_1971__5_1_105_0/}
}

Boulaye, Guy. Notions d'extension dans les treillis. ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique, Tome 5 (1971) no. R1, pp. 105-116. http://archive.numdam.org/item/M2AN_1971__5_1_105_0/