This list contains all the sources a release date can be found. Some are more, some less accurate. The less accurate ones could be shown for replacement within a special search option.
- Copyright date
Found on the cover/title screen, should be replaced when better info is found. - Bought-on-release-day date
A trustworthy collector proves he/she did buy a game on day of release. - File date
On some platforms (like DOS or Windows), the files saved on the media have dates to it. - Official release date
From publisher's or developer's website. - Involved party release date
All dates taken from the gaming press, software shop website, or other source with more reliability than none. - Outside release date
This is an exception. Taken from another gaming website or wikipedia, temporary and is tagged as such and needs to be verified with better sources.
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