I f you follow the links you will see some material from an LDS source, but the original and primary sources of information on the beliefs of native americans and their ancestors come from the records kept by explorers and the conquerers who established the 'New world', Christian and Catholic priests, journalists and even accountants who made records of the amazing culture, beliefs, practises and history of the various native peoples. Most information was lost though through the tragedy of the destruction of the culture, artwork, pottery and records of the native peoples by those seeking to replace it with Euorpean culture and religion.
There are also many scientific sources. Scientist who in their respective disciplines, studied the art, culture, contruction, transportation, theology, husbandry , politics, war, medicine and even surgery through artifacts excavated and found from time to time of the last few centuries.