Random Wikipedia quotes aren’t verifiable, and thus aren’t valid sources in this context.
But to keep in the spirit of debate, Communist sources would be suspect, as would Tibetan ones. Neutral bystanders or third parties have less incentive to misrepresent events and context to put their side in a better light, like Communist and Tibetans would both naturally be suspected to be doing.
Do you have any third party sources for these time periods and events?