Milbank

Milbank, Samuel R. The Coinage of Aegina. Numismatic Notes and Monographs No. 24. (New York, 1925).

66 pages, 5 fold-out plates. An early but still valuable study of the turtle coinage of Aegina. 12mo. Tan card covers. Rare. Copies sell for $100 - $350.

Available online: http://babel.hathitrust.org/cgi/pt?id=uc1.%24b460910

or http://babel.hathitrust.org/cgi/pt?id=mdp.39015009062988 (bundled)

Countermarks found on Aegina turtle coins...

Aeginetic standard

Didrachm or Stater ... 12.57g
Drachm................ 6.28g
Hemidrachm or Triobol 3.11g
Diobol................ 2.07g
Trihemiobol........... 1.55g
Obol.................. 1.04g
Hemiobol...............0.52g
Tetartemorion..........0.26g