@article{MM2_1994__83_3-4_155959,
     author = {Alexander Kushkuley and Zalman Balanov},
     title = {A comparison principle and extension of equivariant maps.},
     journal = {Manuscripta mathematica},
     pages = {239--264},
     publisher = {mathdoc},
     volume = {83},
     number = {3-4},
     year = {1994},
     zbl = {0829.55002},
     url = {http://geodesic.mathdoc.fr/item/MM2_1994__83_3-4_155959/}
}