@article{CRMATH_2012__350_15-16_753_0,
     author = {Guan, Qi'an and Zhou, Xiangyu},
     title = {Optimal constant problem in the $ {L}^{2}$ extension theorem},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {753--756},
     publisher = {Elsevier},
     volume = {350},
     number = {15-16},
     year = {2012},
     doi = {10.1016/j.crma.2012.08.007},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2012.08.007/}
}