@article{700880,
     title = {On Urysohn's lemma},
     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 = {111-114},
     mrnumber = {MR0238744},
     zbl = {0162.54601},
     url = {http://dml.mathdoc.fr/item/700880}
}

Dowker, C. H. On Urysohn's lemma, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books,  (1967), pp. 111-114. http://gdmltest.u-ga.fr/item/700880/