Oh thou to friendship most untrue....
MLA
Lamb, Caroline, Lady, 1785-1828. Oh thou to friendship most untrue..... Box 1 | Folder 81. 1822 Jan 31. https://collections.library.yale.edu/catalog/16568576.
APA, 6th edition
Lamb, Caroline, Lady, 1785-1828. (["Box 1 | Folder 81"])(1822 Jan 31)[Oh thou to friendship most untrue....]. https://collections.library.yale.edu/catalog/16568576.