- LIST OF USEFUL LINKS - Job Research Association Bernard Gregory From PhD to employment. Spires Cosmo coffee Online articles arXiv: Preprint server. SPIRES: Advanced database based on arXiv preprints. Packages CMBquick is a package for Mathematica in which tools are provided to compute the spectrum and bispectrum of CMB. xPand is a package for Mathematica, which is loaded on top of xAct (see below) in which tools are provided to compute cosmological perturbations around homogeneous spacetimes. xAct: A package for mathematica performing abstract tensor calculus and even more. Blog Le blog "Le dernier carbone" sur l'énergie, le climat et l'économie. The blog "The last carbon" on energy, climate and economics.