It's easy to cite LitCharts for use in academic papers and reports.
MLA
O'Dwyer, Deirdre. "The Adventures of Tom Sawyer." LitCharts. LitCharts LLC, 22 Jul 2013. Web. 5 Jun 2020.
Chicago
O'Dwyer, Deirdre. "The Adventures of Tom Sawyer." LitCharts LLC, July 22, 2013. Retrieved June 5, 2020. https://www.litcharts.com/lit/the-adventures-of-tom-sawyer.