Which following would you consider to determine if the source has any bias

You will have to look at whether or not the creator of the source had a really positive or negative outlook on the situation.

If they are -for example- great friends with a bully, they will not tell as much of the truth, but if they are enemies, they may tell a very exaggerated truth to get them in trouble.

You must look for a very neutral feeling on both sides of the matter. If the author has an opinion, more likely than not it will affect the way they share the information

answer; andrew jackson approved nullification by signing it into law,and john calhoun opposed it saying it was unconstitutional;