United Nations Convention on the Rights of the Child, November 20, 1989, https://www.ohchr.org/en/professionalinterest/pages/crc.aspx
(United Nations Convention on the Rights of the Child, 1989)
Most treaty APA citations have these basic elements:
United Nations Convention on the Rights of the Child,
November 20, 1989,
https://www.ohchr.org/en/professionalinterest/pages/crc.aspx
See The University of Akron's Bluebook Quick Reference: Abbreviations and How-tos for help with abbreviations​.
See Publication Manual, 11.10