Over the years, Nathan P. Butler has been fortunate enough to contribute to other professional publications, usually in an unpaid advisory or interviewee capacity.
Star Wars: The Essential Atlas
(Daniel Wallace and Jason Fry)

For this 2009 Star Wars Essential Guide from Del Rey, writen by Daniel Wallace and Jason Fry, Butler developed in-universe, digital calendar dates that were then used for twelve dated maps. Dated battle map dates were derived for The Road to Coruscant, The Hunt for Zsinj, and The Thrawn Campaign. Duration dates for another trio of maps for The New Jedi Order events were derived with the help of Eddie van der Heijden. Finally, film start dates for the six live action Star Wars films were re-confirmed and provided, along with a brand new digital date for Return of the Jedi, which Butler provided.

Star Wars Super Collector's
Wish Book, 4th Ed.
(Geoffrey Todd Carlton)

For this 2007 edition of G.T. Carlton's Star Wars Super Collector's Wish Book, Butler provided an article on Star Wars chronology, which appears only in this fourth edition of the book.

Using the Force:
Creativity, Community, and Star Wars Fans
(Will Brooker)

For this 2002 study on Star Wars fandom, Butler was one of the study's interview subjects and appears in two sections of the book.

Star Wars: The New Essential
Guide to Characters
(Daniel Wallace)

For this 2002 Star Wars Essential Guide, Butler did not actively provide material to the author, but the author utilized Butler's Star Wars Timeline Gold fandom project when writing the book.