What is the current measured density contrast inside the cosmological voids of radius about 30 Mpc? By measured I mean somebody constructed a density map based on peculiar velocities map or weak lensing. I've read a Paper by L. da Costa - Astrophysical Journal 468, L5, 1996 - that constructed a density map of our neighbourhood (radius about 100 Mpc) based on measured peculiar velocities of galaxies. According to the density contours the matter (visible and dark) density inside the voids around us drops to about 20% of the average i.e. density contrast = -0.80. Has anyone seen more recent paper that measure the matter density in the voids?