@article{700881,
     title = {Algebraic generalization of the topological theorems of Bolzano and Weierstrass},
     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 = {361-362},
     zbl = {0161.41901},
     url = {http://dml.mathdoc.fr/item/700881}
}

Zervos, S. P. Algebraic generalization of the topological theorems of Bolzano and Weierstrass, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books,  (1967), pp. 361-362. http://gdmltest.u-ga.fr/item/700881/