Emmett

Emmett, Keith.  Alexandrian Coins. (Lodi, WI, 2001).

Exclusively for Alexandrian coinage (Roman Egypt) and contains an extensive cataloging system that allows for new coins, rarity, drawing of all coin obverses and reverses, maps and a concordance to other references. It was designed to be exhaustive in scope but it is more like a reverse type catalog by Emperor/ denomination/ reverse type and regnal date. It provides a rarity value for each coin from R1 to R5. The regnal dates for each ruler are given with the general obverse types on the coins. Obverse inscriptions are given as a general guide only. There is reverse type index at the back and one reference per coin is given a citation to another collection.

Rarity (FORVM interpretation)

R1 Very Common
R2 Common
R3 Scarce to Very Scarce
R4 Rare
R5 Very Rare
? Either authenticity or date of the specimen is suspect
t Type description details are uncertain (could be a different type)
d Direction of bust or reverse figure is uncertain (could be a different type or variant)
s Denomination (size) is uncertain (could be a different denomination)