It's easy to cite LitCharts for use in academic papers and reports.
MLA
Arn, Jackson. "Mere Christianity." LitCharts. LitCharts LLC, 12 Jan 2017. Web. 5 Jul 2020.
Chicago
Arn, Jackson. "Mere Christianity." LitCharts LLC, January 12, 2017. Retrieved July 5, 2020. https://www.litcharts.com/lit/mere-christianity.