Heinloth, Jochen (January 29, 2009), "Lectures on the Moduli Stack of Vector Bundles on a Curve", Affine Flag Manifolds and Principal Bundles, Basel: Springer Basel (published 2010), pp. 123–153, doi:10.1007/978-3-0346-0288-4_4, ISBN978-3-0346-0287-7