These sources seem to bve biblical in nature. The roman law, structure of government, military, civil service etc. served as a model for future european governments and are easilly identifiable in the US constitution and government. The romans were pagans when these institution were established. The Greeks including Platos Republic and democratic philosophies got the whole ball started.
If it is the intent of this site to support the US as a Christian nation, then let us know. If the intent to to identify sources for the US as a country and government then the pagans must get their due and the cite has a serious omission problem.