[Letter : W[illia]m Petty, 1654 January 23 to Samuel Hartlib]
MLA
Petty, William, Sir, 1623-1687. [Letter : W[illia]m Petty, 1654 January 23 to Samuel Hartlib]. Folder 16800. 1654 January 23. https://collections.library.yale.edu/catalog/10034166.
APA, 6th edition
Petty, William, Sir, 1623-1687. (["Folder 16800"])(1654 January 23)[[Letter : W[illia]m Petty, 1654 January 23 to Samuel Hartlib]]. https://collections.library.yale.edu/catalog/10034166.