(undent)Wikipedia rules say the following: 
 Websites and publications of political parties, religious groups, anti-religious groups, or any other partisan group, may exhibit bias and should be treated with caution. Neither political affiliation nor religious belief stated in these sources are in themselves a reason not to use them, as these websites can be used to present the viewpoints of these groups, if properly attributed. Such sources should be presented alongside references from other sources in order to maintain a neutral point of view.