Here are 109 articles (or books) http://arxiv.org/cits/gr-qc/0102069?skip=75&db=spires which all cite Bojowald's landmark paper where he determined that in Loop cosmology gravity REPELS at very high density. Here is the orig: http://arxiv.org/gr-qc/0102069 [Broken] the original paper dealt with an isotropic case (the analysis was simplified by making things uniform or symmetric) but since then people have extended the result, assuming less and less, to make it more general. AFAICS this has no direct connection with the "anti-gravitation" that Sabine H is discussing in her thread of that name. But maybe it is an amusing coincidence. In any case there is a considerable literature now which takes seriously the possibility that the effect of gravity reverses at very high density, and becomes repellent. Bojowald, Singh, and others have modeled stellar-size collapse in some detail and Singh has proposed that the model may have an observable signature which can be sought in GRBs. In any case reversed gravity is a feature of the LQC model, which has the correct classical limit and is currently being studied for observational testing.