Analysis of information sources in references of the Wikipedia article "Velódromo de Anoeta" in English language version.
...se inauguró como pista de ciclismo y graderío en 1965 para unos Mundiales de ciclismo. Tuvo que llegar otro Mundial de ciclismo en 1973 para que se cubriera la pista. (It was opened as cycling track il 1965 for Track World Championships. It was not until another Word Championships in 1973 that the track was covered)
