Serious encyclopedias: Serious and respected encyclopedias and reference works are generally expected to provide overviews of scientific topics that are in line with respected scientific thought. Wikipedia aspires to be such a respected work.
3. Questionable science: Theories which have a substantial following, such as psychoanalysis, but which some critics allege to be pseudoscience, may contain information to that effect, but generally should not be so characterized.
4. Alternative theoretical formulations: Alternative theoretical formulations which have a following within the scientific community are not pseudoscience, but part of the scientific process.