VarietyPlus service is also available for coins already encapsulated by NGC.
For coins where the fee column is blank, no VarietyPlus charge is required to
have your coin designated during grading. For coins marked $15, a $15 surcharge
applies to the tier fee during grading, or a $15 fee applies to have the VarietyPlus
designation added to any coin already graded and encapsulated by NGC.
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Breen, Walter. Walter Breen’s Complete Encyclopedia of U.S. and Colonial Coins. Doubleday/FCI Press, New York, 1988
Feigenbaum, John. The Complete Guide to Washington Quarters. DLRC Press, Virginia Beach, 1994
Lange, David W. History of the United States Mint & Its Coinage. Whitman Publishing, Atlanta, 2005
Taxay, Don. The U.S. Mint and Coinage. Arco Publishing, New York, 1966
Wexler, John A. & Kevin Flynn. The Best of the Washington Quarter Doubled Die Varieties. Stanton Printing & Publishing, Savannah, GA, 1999
Wiles, James, Ph.D. The Washington Quarter Dollar Book: An Attribution and Pricing GuideThe Washington Quarter Dollar Book: An Attribution and Pricing Guide, Volumes One through Three. CONECA, 2002
Yeoman, R.S., Kenneth Bressett (editor). A Guide Book of United States Coins, 62nd Edition. Whitman Publishing, Atlanta, 2008