APA (7th ed.) Citation

Sotheby's (Firm). (1991). Old master, 19th and 20th century and contemporary prints ... 12-13 December 1991 Catalogue. Sotheby's.

Chicago Style (17th ed.) Citation

Sotheby's (Firm). Old Master, 19th and 20th Century and Contemporary Prints ... 12-13 December 1991 Catalogue. London: Sotheby's, 1991.

MLA (9th ed.) Citation

Sotheby's (Firm). Old Master, 19th and 20th Century and Contemporary Prints ... 12-13 December 1991 Catalogue. Sotheby's, 1991.

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