Here is the opinion in Fond du Lac Band of Lake Superior Chippewa v. Frans: CA8 opinion in Fond du Lac.
From the court’s syllabus:
Minnesota’s act in taxing a Band member’s pension, earned in Ohio, but received on the reservation, did not violate due process as the member’s Minnesota citizenship created a constitutional nexus for the taxation. Judge Murphy, dissenting.
And the briefs:

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