APA (7th ed.) Citation

Butler, J., & Hoskin, M. A. (1987). The Archives of Armagh Observatory.

Chicago Style (17th ed.) Citation

Butler, John, and Michael A. Hoskin. The Archives of Armagh Observatory. 1987.

MLA (9th ed.) Citation

Butler, John, and Michael A. Hoskin. The Archives of Armagh Observatory. 1987.

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