@article{700763,
     title = {Some Tietze type extension theorems},
     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 = {1972},
     pages = {23-27},
     mrnumber = {MR0367905},
     zbl = {0317.54024},
     url = {http://dml.mathdoc.fr/item/700763}
}

Alò, R. A. Some Tietze type extension theorems, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books,  (1972), pp. 23-27. http://gdmltest.u-ga.fr/item/700763/