  We show that the manifestation of quantum interference in graphene is very
different from that in conventional two-dimensional systems. Due to the chiral
nature of charge carriers, it is sensitive not only to inelastic,
phase-breaking scattering, but also to a number of elastic scattering
processes. We study weak localization in different samples and at different
carrier densities, including the Dirac region, and find the characteristic
rates that determine it. We show how the shape and quality of graphene flakes
affect the values of the elastic and inelastic rates and discuss their physical
origin.
