^Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2017). "Huabei Guanhua". Glottolog 3.0. Jena, Germany: Max Planck Institute for the Science of Human History.
^Margaret Mian Yan Introduction to Chinese Dialectology 2006 - Page 62 "Jiao–Liao Mandarin Group 胶辽官话The estimated number of native speakers of this group is 28.83 million; it is divided into the following subgroups: ; (1) Qingzhou subgroup (2) Deng–Lian subgroup (3) Gai–Huan Subgroup 5. Zhongyuan Mandarin ..."