Quan, Xiao-Wei; Hoerling, Martin P.; Perlwitz, Judith; Diaz, Henry F.; Xu, Taiyi (March 1, 2014). "How Fast Are the Tropics Expanding?". Journal of Climate. 27 (5): 1999–2013. Bibcode:2014JCli...27.1999Q. doi:10.1175/JCLI-D-13-00287.1.
Quan, Xiao-Wei; Hoerling, Martin P.; Perlwitz, Judith; Diaz, Henry F.; Xu, Taiyi (March 1, 2014). "How Fast Are the Tropics Expanding?". Journal of Climate. 27 (5): 1999–2013. Bibcode:2014JCli...27.1999Q. doi:10.1175/JCLI-D-13-00287.1.