A comparison between resonance widths computed via the single-harmonic approximation vs. numerical averaging for resonances up to fourth order between the 3:2 and 4:3 MMRs. Blue lines show single-harmonic model resonance separatrices computed using Equation (5) (with ﹩{S}_{j,k}﹩ given by Equation (23)). Black lines show resonance separatrices computed via numerical averaging following the methods of Morbidelli et al. (1995). Equation (5) does not capture the special behavior of first-order resonances near e = 0, where the separatrix wide of the nominal resonance location disappears as seen in resonance widths computed via numerical averaging.