@article{10_4153_CJM_2009_040_8,
     author = {Caprace, Pierre-Emmanuel and Haglund, Fr\'ed\'eric},
     title = {On {Geometric} {Flats} in the {CAT(0)} {Realization} of {Coxeter} {Groups} and {Tits} {Buildings}},
     journal = {Canadian journal of mathematics},
     pages = {740--761},
     year = {2009},
     volume = {61},
     number = {4},
     doi = {10.4153/CJM-2009-040-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2009-040-8/}
}