APA (7th ed.) Citation

Webster, M. (1989). Webster's Encyclopedic Unabridged Dictionary of the English Language. Portland house.

Chicago Style (17th ed.) Citation

Webster, Merriam. Webster's Encyclopedic Unabridged Dictionary of the English Language. Portland house, 1989.

MLA (8th ed.) Citation

Webster, Merriam. Webster's Encyclopedic Unabridged Dictionary of the English Language. Portland house, 1989.

Warning: These citations may not always be 100% accurate.