I will reference something like a normative set if I am using something that is not manualized or widely known. For example, There are high quality MoCA norms that more accurately capture older adults living independently in the community that are a far better indicator than the blanket "greater or equal to 26" that people blindly follow. I just cite the article, if they want the full article, they can find it themselves, or ask me, no need for a reference section. And, I agree with other posters, no need to reference something like "polypharm is bad," or "maybe you shouldn't give Xanax to my older patients with dementia," or "donepezil is useless." These are things that most good doctors should know. The only people for whom these are controversial statements are incompetent prescribing providers who are too lazy to deliver good care to their patients.