The projectivity of the moduli space of stable curves, III: The line bundles on $M_{g,n}$, and a proof of the projectivity of $\bar{M}_{g,n}$ in characteristic 0.

Knudsen, F. F. (1983). The projectivity of the moduli space of stable curves, III: The line bundles on $M_{g,n}$, and a proof of the projectivity of $\bar{M}_{g,n}$ in characteristic 0. MATHEMATICA SCANDINAVICA, 52, 200–212. https://doi.org/10.7146/math.scand.a-12002