Does anyone know the dates for 2008 Swan Lake at Chapultepec Lake in Mexico City?

Question

Where can I buy tickets?

Answer 1

According to the New York Times

On evenings in April and May, a local ballet company performs ''Swan Lake'' with Chapultepec Castle and Lake as a backdrop. Thanks to soft lighting and the angle of the stage, the performers appear to be dancing on the lake. Tickets for this springtime tradition are avidly sought but can usually be acquired at travel agencies or at the Palacio de Las Bellas Artes downtown.

and American Airlines says

This small island in Chapultepec Lake is the ideal setting to initiate oneself in the appreciation of ballet, or for the children to start familiarising themselves with this beautiful art. Each year during the months of March and April, the National Dance Company interprets the classic Swan Lake Ballet. The show is presented outdoors, and the forest surrounding the lake is turned into a natural stage, which is ideal for the enjoyment and contemplation of the sights and sounds. Presentations are held on Thursdays, Fridays and Saturdays at 8p. You may get your tickets in advance through the Ticketmaster system.

The City Guide Travel guide has lots of cultural links, but unfortunately, no link to the Mexico National Dance Company.  Maybe someone here will know it.  I looked but couldn't find it.