With respect to the publication in the Proceedings of the IAU Colloquium 180 (Dehant 2000), I have a few additional remarks that I would like to make. There were three competing models:

1. MHB2000 of Mathews et al. (2000), (see also Mathews 2000), constructed from a rigid Earth nutation series with about 1400 terms and a transfer function obeying the sum rules, based on the fit of a semianalytical nutation theory to VLBI observations, with resonances determined by geophysical parameters including those estimated from the fit, incorporating the atmospheric annual effect fitted to observations, including ocean tide effects based on admittances with frequency dependence due to the FCN (Free Core Nutation) resonance and to ocean dynamics (fitted to ocean tide data), including electromagnetic couplings of the fluid core, and with mutual consistency maintained in the treatments of nutations, solid Earth tides and ocean tides which influence one another;

2. GF2000 of Getino and Ferrándiz (2000), using a global Hamiltonian approach for 106 waves fitted to VLBI data, incorporating a resonance with global parameters fitted to observations such as the FCN free mode frequency, compliances, and dissipation coefficients, incorporating ocean corrections from Huang et al. (2000) with a frequency dependent resonance and fitted atmospheric corrections, and necessitating empirical corrections;

3. SF2000 of Shirai and Fukushima (2000a and 2000b) or Herring (2000, not published), empirical models, based on a simple resonance formula fitted to the VLBI observation.