In addition to Malayo-Polynesian, thirteen Formosan subgroups are broadly accepted. The seminal article in the classification of Formosan—and, by extension, the top-level structure of Austronesian—is . Prominent Formosanists (linguists who specialize in Formosan languages) take issue with some of its details, but it remains the point of reference for current linguistic analyses. Debate centers primarily around the relationships between these families. Of the classifications presented here, links two families into a Western Plains group, two more in a Northwestern Formosan group, and three into an Eastern Formosan group, while also links five families into a Northern Formosan group. splits Tsouic, and notes that Tsou, Rukai, and Puyuma fall outside of reconstructions of Proto-Austronesian.