1. Boucher, C., Altamimi, Z., Feissel, M., & Sillard, P. 1996, IERS Technical Note 20, Central Bureau of IERS, Observatoire de Paris
2. Boucher, C., Altamimi, Z., & Sillard, P. 1998, IERS Technical Note 24, Central Bureau of IERS, Observatoire de Paris