The letter concerns Duthie's symposium, which cannot be identified; it may have been for a magazine. It was offered for sale by Maggs Brothers, catalogue 971, spring 1976. The catalogue contains an extract from the letter: "I am at the moment exceedingly busy, or I would send you with pleasure a contribution to your symposium. As it is, I send you a guinea for your funds, with warm wishes [for a successful campaign]." The bracketed words appear only in Houle's catalogue entry on Abebooks.com.

Houle Rare Books, Los Angeles, offered the letter for sale again in March 2012. (The price rose from £14 in 1976 to $1,750 in 2012.)