@article{MZ_1974__136_172024,
     author = {Robert L. Blair and Hager Anthony W.},
     title = {Extensions of {Zero-sets} and of {Real-valued} {Functions.}},
     journal = {Mathematische Zeitschrift},
     pages = {41--52},
     publisher = {mathdoc},
     volume = {136},
     year = {1974},
     zbl = {0264.54011},
     url = {http://geodesic.mathdoc.fr/item/MZ_1974__136_172024/}
}