Research
When critically evaluating sources it is good to remember OPVL and POOP
O - Origin: Who wrote this source? Who are they? When did they write it? Where did they write it?
P - Purpose: Why did they write it? What is their agenda? Why write another book on this topic?
V - Value: What is the value of this source for my current research or investigation?
L - Limitations: What are the limitations of this source for my current research or investigation?
P - Primary or secondary source?
O - Objective or does the author have a reason to lie?
O - Other sources that corroborate or back up this author's point of view?
P - Professional historian or not?
Some research links: