"The Exercise of External Self-Determination by Indigenous Groups: The Republic of Lakotah and the Inherent Sovereignty of American Indian Peoples"

http://heinonline.org/HOL/Page?handle=hein.journals/sljicla1&div=7&g_sent=1&collection=journals

A 2015 article on the Republic of Lakotah
"The Exercise of External Self-Determination by Indigenous Groups: The Republic of Lakotah and the Inherent Sovereignty of American Indian Peoples" Sarah Sargent and Graham Melling