Cohen, Roger S., American Half Cents, the "Little Half Sisters": A reference book on the United States half cent coined from 1793 to 1857, Arlington, Virginia, USA, 1982, Wigglesworth & Ghatt Co; 2nd edition, 131 pages, hardcover, although the rarity ratings are outdated, it is still an excellent reference for the half cent collector.
Estimate: 20-30 USD