On page 2543, the bipolar scheme uses two gradient pulses for encoding, and two other gradient pulses for decoding. Thus, Equation 1 should be S/S0 = exp{-D4k2(D + 6t)}, rather than S/S0 = exp{-Dk2(D + 6t)}, as published. The incorrect expression would lead to an overestimation of the diffusion coeff. D by a factor of 4. This correction does not affect the results shown in Figure 3 or the diffusion coeffs. quoted in the paper. [on SciFinder (R)]