@article{CRMATH_2006__342_4_253_0,
     author = {Hu, B.Z.},
     title = {Relative hyperbolization and {Pontrjagin} classes},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {253--257},
     publisher = {Elsevier},
     volume = {342},
     number = {4},
     year = {2006},
     doi = {10.1016/j.crma.2005.12.020},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2005.12.020/}
}