Quarter: https://en.numista.com/catalogue/pieces56.html
Half: https://en.numista.com/catalogue/pieces1489.html
Dollar: https://en.numista.com/catalogue/pieces3366.html
These are listed as 1976 coins, but they really should be ND coins for consistency with https://en.numista.com/catalogue/pieces6935.html (1/12 Shilling 1066-1966) and other similar coins as discussed in https://en.numista.com/forum/topic83784.html .
The coins were minted over two years (1975 and 1976). Sources:
https://www.usmint.gov/coins/coin-medal-programs/circulating-coins/george-washington-bicentennial-quarter
https://en.wikipedia.org/wiki/United_States_Bicentennial_coinage