2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/133017The bifurcation structure of the Langford equation is studied numerically in detail. Periodic, doubly-periodic, and chaotic solutions and the routes to chaos via coexistence of double periodicity and period-doubling bifurcations are found by the Poincaré plot of successive maxima of the first mode $x_1$. Frequency-locked periodic solutions corresponding to the Farey sequence $F_n$ are examined up to $n=14$. Period-doubling bifurcations appears on some of the periodic solutions and the similarity of bifurcation structures between the sine-circle map and the Langford equation is shown. A method to construct the Poincaré section for triple periodicity is proposed.9 pages, 10 figures, 2 tables, submitted to JJIAMFluid DynamicsGeneral Physicstext