@article{700684,
     title = {Covering dimensions and partitions of unity},
     booktitle = {General topology and its relations to modern analysis and algebra IV},
     series = {GDML\_Books},
     publisher = {Society of Czechoslovak Mathematicians and Physicist},
     address = {Praha},
     year = {1977},
     pages = {159-163},
     mrnumber = {MR0458387},
     zbl = {0372.54034},
     url = {http://dml.mathdoc.fr/item/700684}
}

Hejcman, J. Covering dimensions and partitions of unity, dans General topology and its relations to modern analysis and algebra IV, GDML_Books,  (1977), pp. 159-163. http://gdmltest.u-ga.fr/item/700684/