A good early paper that goes into some detail about the parameters and
theory is:
Measurement of Slow (s-ms) Time Scale Dynamics in Protein Side Chains by 15N Relaxation Dispersion NMR Spectroscopy: Application to Asn and Gln Residues in a Cavity Mutant of T4 Lysozyme
Frans A. A. Mulder, Nikolai R. Skrynnikov, Bin Hon, Frederick W. Dahlquist, and Lewis E. Kay*
J. Am. Chem. Soc., 123 (5), 967 -975, 2001. 10.1021/ja003447g S0002-7863(00)03447-8
Web Release Date: January 16, 2001
although it is aimed at only at sidechain amide groups.
A more comprehensive review can be found at:
A.G. Palmer, C.D. Kroenke and J.P. Loria, NMR methods for quantifying microsecond-to-millisecond motions in biological macromolecules, Methods Enzymol. 339 (2001), pp. 204–238.
Hope this helps