A couple of people have asked for more information about the article by Fr Lang on the Anaphora of Addai and Mari. The article was entitled "Eucharist without institution narrative? The anaphora of Addai and Mari revisited" and was written in the 2004 edition of the journal Divinitas published at the Vatican. (Source and online ordering information.)
There was a notice about the article in the German kreuz.net:
Das Rätsel der Liturgie von Addai und Mari.
I understand that Fr Lang may be intending to publish this material more widely in due course.