Reshetikhin, N. (2010). Lectures on the integrability of the 6-vertex model. I J. Jacobsen, S. Ouvry, V. Pasquier, D. Serban & L. Cugliandolo (red.), Exact methods in low-dimensional statistical physics and quantum computing: Lecture notes of the Les Houches Summer School: volume 89, July 2008 Oxford University Press.