Interesting question, unfortunately I have no answer, but I did attempt to look for 15 minutes after seeing this. Now you have
my curiosity piqued

and I'm sure one of our erudite members will come along with an answer - they always do!

_________________________
The bond that links your true family is not one of blood, but of respect and joy in each other's life. Rarely do members of one family grow up under the same roof.-- Richard Bach [i]Illusions