You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Buddhism

Context:
According to Mahayana tradition, the Mahayana sutras were transmitted in secret, came from other Buddhas or Bodhisattvas, or were preserved in non-human worlds because human beings at the time could not understand them:

Question:
What sutras could have been preserved in non-human worlds?

Mahayana