I picked this Trajan Alexandrian Tetradrachm up at the FUN show today but I can't seem to find a reference for it. It's not in Emmett or any of the typical online reference sites. Any ideas? Here it is: Appears to be a pair of oxen pulling a cart with vase; head of Serapis above oxen; LIB (year 12) in upper field. The coin is 34mm and 22.1 gms and the tag with it I believe says Seaby 1950, although it's not very clear.