Exec. Order No. 13,676, 3 C.F.R. 294 (2014). https://www.govinfo.gov/content/pkg/CFR-2015-title3-vol1/pdf/CFR-2015-title3-vol1-eo13676.pdf
(Exec. Order No. 13,676, 2014)
Most executive order APA citations have these basic elements:
Exec. Order No. 13,676,
3 C.F.R.
294
(2014).
https://www.govinfo.gov/content/pkg/CFR-2015-title3-vol1/pdf/CFR-2015-title3-vol1-eo13676.pdf
See The University of Akron's Bluebook Quick Reference: Abbreviations and How-tos for help with abbreviations​.
See Publication Manual, 11.7