In 1928 Riesz published a formula for counting JNDs Delta I(I). This formula says that the number of JNDs between I1 and I2 is given by the integral of 1/Delta(I), integrated between the limits I1 and I2. My question is, does any one know if this formula is in any text books or papers? If so, please give me the most popular reference or two where I might find it discussed. jont allen