APA (7th ed.) Citation

Hartwell, F. P. (2021). McGraw-Hill's National Electrical Code 2020 Handbook, 30th Edition (Thirtieth edition.). McGraw-Hill Education.

Chicago Style (17th ed.) Citation

Hartwell, Frederic P. McGraw-Hill's National Electrical Code 2020 Handbook, 30th Edition. Thirtieth edition. New York, N.Y.: McGraw-Hill Education, 2021.

MLA (9th ed.) Citation

Hartwell, Frederic P. McGraw-Hill's National Electrical Code 2020 Handbook, 30th Edition. Thirtieth edition. McGraw-Hill Education, 2021.