Adventure No. 13 - The Sorcerer of Claymorgue Castle

I see that there are copyrights given
as 81 (tape)and 83 (disk), but perhaps these are just refering to the engine/interpreter? Or maybe it just wasn't released commerically until 83 (or 84, can't be sure). The ad here implies the game was newly released, so where was it taken from?

Seems unlikely that this was released in 1981, it doesn't appear before 1983 in Adventure International's catalogs. Probably the same date as the disk version.