{"id":"000030476","type":"book","title":"Why did the pre-columbian Maya civilization collapse? - Washington, D.C. Symposium held in Santa Fe, NM 19-24 Oct. 1970","container-title":"Science ; 173.1971, no. 3997, S. 656-658","author":[{"family":"Willey","given":"Gordon R. 1913-2002."}],"issued":{"raw":"1971"}}