@article{JEMS_2017_19_4_a6,
     author = {Pekka Koskela and Jie Xiao and Yi Ru-Ya Zhang and Yuan Zhou},
     title = {A quasiconformal composition problem for the $Q$-spaces},
     journal = {Journal of the European Mathematical Society},
     pages = {1159--1187},
     publisher = {mathdoc},
     volume = {19},
     number = {4},
     year = {2017},
     doi = {10.4171/jems/690},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/690/}
}