MLA

England and Wales. Lord Protector (1653-1658 : O. Cromwell). Proclamations, 1658, Dec. 16. A declaration of His Highnesse the Lord Protector for a day of solemn fasting and humiliation ... : given at Whitehall this sixteenth day of December one thousand six hundred fifty and eight. 1658. https://collections.library.yale.edu/catalog/2019783.

APA, 6th edition

England and Wales. Lord Protector (1653-1658 : O. Cromwell). Proclamations, 1658, Dec. 16. (1658)[A declaration of His Highnesse the Lord Protector for a day of solemn fasting and humiliation ... : given at Whitehall this sixteenth day of December one thousand six hundred fifty and eight]. https://collections.library.yale.edu/catalog/2019783.