I don't have the book "Monograms of American Coin & Medal Artists" and was wondering whether LKS is listed. I recently purchased a beautiful George Washington plaque (bearing the dates 1732-1932) with the above initials in the lower left corner. After doing a web search I determined they were the initials of Louise Kidder Sparrow (1884-1979) who among other things was noted for her plaques and poetry.