What were thw main points of Monroe doctrine?

I hope this helps hun:)

1) the United States would not interfere in the internal affairs of or the wars between European powers; (2) the United States recognized and would not interfere with existing colonies and dependencies in the Western Hemisphere; (3) the Western Hemisphere was closed to future colonization; and (4) any attempt by a European power to oppress or control any nation in the Western Hemisphere would be viewed as a hostile act against the United States.

because mexico wanted to choose a centralized location

do you have a list of sources to choose from?