From the introduction: "Ergativity has long been an important topic in linguistic research, from both a typological (Comrie 1978, Dixon 1979, Plank 1979) as well as a theoretical perspective (Levin 1983, Marantz 1984). The purpose of the present study is to contribute to the discussion of this phenomenon via a study of a fragment of the grammar of Karitiana, an Amazon language, focusing especially on its ergative-absolutive marking of affirmative particles and personal pronouns. The special features of the Karitiana (henceforth K) system are: (1) only absolutive marking need be stated by rule, ergative case being a default mechanism, and (2) K's ergative marking offers interesting evidence in favor of the distinction between topicalization and WH-movement, along the lines first proposed by Chomsky (1977)."
Everett, Daniel L.
"A note on ergativity, S', and S'' in Karitiana,"
Work Papers of the Summer Institute of Linguistics, University of North Dakota Session: Vol. 29, Article 2.
Available at: https://commons.und.edu/sil-work-papers/vol29/iss1/2