I was recently following up references in two different books, trying to track down the text of the Austro–Hungary Japan Treaty of 1869 – I know, some people have funny hobbies. Both referred to a collection published by the Japanese Foreign Ministry in 1899.

But when I tracked this down online, I found that it only dealt with treaties that were then currently in force, and the 1869 treaty, like all the other “unequal treaties”, had just been superseded. Carelessness or dishonesty? Then I checked again and the mistake was mine: while there was some ambiguity in one of the footnotes, I had misread the date in the other.