Robuta

https://www.siue.edu/human-resources/faqs/pages/who-is-a-nonresident-alien-and-resident-alien-for-tax-purposes.shtml

https://www.irs.gov/zh-hans/statistics/soi-tax-stats-nonresident-alien-estate-tax-study-terms-and-concepts

https://www.ssa.gov/international/AlienTax_Page1.html