@article{AM2_1972__8_136279,
     author = {P. Erd\"os and J. Marshall Ash and L.A. Rubel},
     title = {Very {Slowly} {Varying} {Functions.} {(Short} {Communications).}},
     journal = {Aequationes mathematicae},
     pages = {191--192},
     publisher = {mathdoc},
     volume = {8},
     year = {1972},
     url = {http://geodesic.mathdoc.fr/item/AM2_1972__8_136279/}
}