From the introduction, "The analysis presented in this paper is based primarily on a body of data comprising seven allomorphic prefixes and a representative number of verb stems listed in their third person singular forms. An earlier, unpublished structural analysis of the same data yielded four ad hoc verb root classes, three of which were divided into subclasses. Even then, certain of the verb root sets did not fit the classification.
"This analysis was done within the generative framework and was especially designed to account for the verb paradigms given in Tables A-E. Any data that may seem to be exceptional to the rules therein require careful consideration before changes are made since certain morphemes (such as -a- (causative)) are marked to not undergo some rules. Where possible, non-verb forms are provided to give additional confirmation of the validity of this analysis. It should be borne in mind that this paper represents an initial attempt to analyze Seri verbs from the generative approach. Considerable refinement will be necessary as study continues."
Marlett, Stephen A.
"A sketch of Seri verb morphophonemics,"
Work Papers of the Summer Institute of Linguistics, University of North Dakota Session: Vol. 20, Article 1.
Available at: https://commons.und.edu/sil-work-papers/vol20/iss1/1