"The top market value for a Diamond-back with a plastron six to seven inches long is six to seven dollars, the value increasing sometimes as much as dollar for every additional half-inch in length."
Clifford H. Pope (1967) Turtles of the United States and Canada
"The most celebrated of American turtles."
Roger Conant (1958) introducing terrapins in his "A Field Guide to Reptiles and Amphibians"