@article{MM2_1978__25_154572,
     author = {Peter Buser},
     title = {The collar theorem and examples.},
     journal = {Manuscripta mathematica},
     pages = {349--358},
     publisher = {mathdoc},
     volume = {25},
     year = {1978},
     zbl = {0402.53028},
     url = {http://geodesic.mathdoc.fr/item/MM2_1978__25_154572/}
}