Helpful infos:
- How to cite a source: Wikipedia:Citing_sources
- How to cite a web page: Template:Cite_web
- How to mark citation needed: Wikipedia:Citation_needed
- Hot to link to other language: Help:Interlanguage_links
- Use date calculation templates / functions: Category:Date_mathematics_templates
- How to mark an outdated article: Template:Outdated_as_of