Gabriel Anrep's "Svenska Adelns Attar-Taflor" (1862); pp. 61 & 755 (see "Tab 35: Nanne Abjornsson"), located here:
https://books.google.com/books?id=3H9EYXYctToC&printsec=frontco...
...and "Biographiskt Lexicon öfver namnkunnige svenska män: Sk - Stj, Volume 15" by Vilhelm Fredrik Palmblad, pages 64-67 (also available online), make it clear that Nanne Abjornsson is the son of Sixten, who's the son of Nils, who's the son of Sixten Sixtensson. These sources also make it clear that this Nanne had a daughter Elin Nannesdotter who married Tubbe Eriksson (and they had daughter Botil Tubbedotter).
However, these sources are older, and have their issues. Does anyone have any primary (and perhaps more modern) resources to substantiate the descendants of Abjörn Sixtensson?
Thanks,
Kevin