I would like to make my lecture notes free, and available to all, but would like to be given credit if others use part of it.

Should it be copyleft, GPL, CC, or others?

What would be a proper notice to insert on the first page?

  • 3
    The GPL is not a good choice; it is designed for source code. Jun 20, 2022 at 10:51
  • 8
    At what point did your research fail you? Jun 20, 2022 at 20:53

1 Answer 1


You are confusing at least two concepts here. Looking at your list of suggestions:

  • "copyleft" is not a license itself, but a property of some licenses which means that any derivative works must use the same (or a very similar) license.
  • "GPL" is not a license itself, but a family of copyleft licenses which includes the "base" GNU General Public License, the GNU Lesser General Public License and the GNU Affero General Public License (and multiple version of each of those licenses). However, the GPL family are best suited for licensing code so would probably not be recommended for lecture notes.
    • The GNU Free Documentation License does exist and is intended for use with documentation. However, it is a license with very marginal use (and some potentially problematic clauses) so is probably not a good choice unless you have a very strong reason to use it.
  • "CC" is not a license itself but a whole family of licenses, which include:
    • CC0, which waives all rights to the fullest extent allowed by law.
    • The Creative Commons Attribution License (generally known as "CC-BY"), a non-copyleft license.
    • The Creative Commons Attribution-Sharelike License ("CC-BY-SA"), a copyleft license.
    • The "NonCommercial" (-NC) and "NoDerivatives" (-ND) versions of the above; these are not open source licenses.

The most common choice for a "requires credit" license for documentation would be CC-BY or CC-BY-SA. If you wish for any derivative works to be made available under a Creative Commons license, you would want CC-BY-SA; if this isn't important to you, you would want CC-BY. The Creative Commons website includes guidance on how to indicate your work is licensed under a Creative Commons license.

  • 1
    GPL is a series of licenses, not a family. The AGPL and LGPL are not part of the GPL, but separate licenses. When the term"GPL" is used, it only ever means GNU General Public License. Jun 22, 2022 at 8:20
  • Wikipedia (which is also the redirect target for "GPL"): "The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses". "Series" vs "family" is not a legally meaningful distinction, but your assertion that GPL only ever means the actual specific GPL is clearly not true. Jun 22, 2022 at 8:31
  • 1
    @PhilipKendallnot to nitpick, but the article you link to refers only to GPLv[123] and GPLv[123]+, and hardly mentions AGPL at all. It seems to me as if it reinforces Remember Monica's assertion, that "GPL" refers to the series GPLv1, GPLv2, and GPLv3, not to the set that includes those three along with the LGPL and AGPL licences. I admit we could do with a term that comprises that whole set, but I'm not sure that "GPL" is it.
    – MadHatter
    Jun 22, 2022 at 12:20
  • Even calling GPLv[123] a "series" implies that, e.g., later versions are successors or replacements for (or just updates to) earlier versions. I know of at least one prominent open source developer who thinks that GPLv3 is not a replacement or successor for GPLv2: youtube.com/watch?v=PaKIZ7gJlRU
    – kc9jud
    Jun 29, 2022 at 23:53
  • The point I was making is that GPL never means LGPL, and so far, no evidence has been shown to the contrary. The legal status of "series" vs. "family" is completely irrelevant, the distinction is that GPL licenses come in a series (distinguished by increasing versions), while the gnu copyleft family of licenses is not a series, but simply a gaggle of different licenses (LGPL, GPL, ...) Jul 8, 2022 at 14:02

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