Y. Rykov, «On the Behaviour of Generalized Solutions to Genuinly Nonlinear First Order Equations for SmaIl and Large Values of Time», Rev. mat. complut., vol. 6, n.º 1, p. 139, ene. 1993, doi: https://doi.org/10.5209/rev_REMA.1993.v6.n1.17860