This page contains reference examples for white papers, including the following:
Department for Business Innovation & Skills. (2016). Success as a knowledge economy: Teaching excellent, social mobility and student choice [White paper]. Crown. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/523396/bis-16-265-success-as-a-knowledge-economy.pdf
Furst, M., & DeMillo, R. A. (2006). Creating symphonic-thinking computer science graduates for an increasingly competitive global environment [White paper]. Georgia Tech College of Computing. https://cis.temple.edu/~giorgio/threads_whitepaper.pdf
White paper references follow the same format as reports, which are covered in the seventh edition APA Style manuals in the Publication Manual Section 10.4 and the Concise Guide Section 10.4
This guidance has been revised from the 6th edition.