MLA

M. R, Mossom, Robert, d. 1679. The king on his throne, or, A discourse maintaining the dignity of a king, the duty of a subject, and the unlawfulnesse of rebellion : delivered in two sermons preached in the Cathedrall church in York / by R.M. .... 1642. By speciall command. https://collections.library.yale.edu/catalog/2065923.

APA, 6th edition

M. R, & Mossom, Robert, d. 1679. (1642. By speciall command)[The king on his throne, or, A discourse maintaining the dignity of a king, the duty of a subject, and the unlawfulnesse of rebellion : delivered in two sermons preached in the Cathedrall church in York / by R.M. ...]. https://collections.library.yale.edu/catalog/2065923.