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- GÉANT Open Source Licensing and Compliance workshop slides, https://e-academy.geant.org/moodle/mod/resource/view.php?id=2869
What is Free Software? , https://www.gnu.org/philosophy/free-sw.en.html
- Guide to open source licenses, https://www.synopsys.com/blogs/software-security/open-source-licenses/
- Top open source licenses and legal risk for developers, https://www.synopsys.com/blogs/software-security/top-open-source-licenses/
- Standardised SPDX licence codes and licence texts, https://spdx.org/licenses/
- University of Pittsburgh Library System – Copyright and Intellectual Property Toolkit, https://pitt.libguides.com/copyright
- WhiteSource – Open Source Licenses Explained, https://www.whitesourcesoftware.com/resources/blog/open-source-licenses-explained/
- Free Software Foundation's free software licences and Non-free Software Licenses – , classified individual licences and their compatibility with GPL, https://www.gnu.org/licenses/license-list.html
- Open Source Initiative (OSI) approved licenses
- By category, https://opensource.org/licenses/category
- Alphabetical https://opensource.org/licenses/alphabetical
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- Permissive licences have simple requirements – to credit original work, describe changes, provide disclaimer…
- Copyleft licences (“reciprocal”, “protective”, “restrictive”, derogatory: “viral”) require the rights to be preserved in derivative works
- If you use any components (libraries) with copyleft, you are obliged to make derived source code available, which may include the entire product/project!
- Permissive – do anything
- MIT – short and simple
- ISC (OpenBSD) – further shortened equivalent
- BSD – some versions require to include the disclaimer
- Apache 2.0 – requires notice of changes, grants licence to patents unless litigating and mentions preservation of trademark rights
- Weak copyleft – file (library) scope
- MPL 2.0 – simple, allows static linking and licence variants with additional terms
- LGPL 2.1 – cleaned text of LGPL 2.0, allows dynamic linking without enforcing copyleft
- LGPL 3.0 – grants use of patents; the end-user must be able to install a modified version – it prohibits closed devices, DRM or hardware encryption or patents retaliation; compatible with Apache2.0
- Strong copyleft – project scope
- GPL 2.0 – often used
- GPL 3.0 – grants use of patents, the end-user must be able to install modified software, compatible with Apache2.0
- AGPL 3.0 (Affero) – network protective: external use of modified(!) code requires its availability – network use is a distribution of the software, modified source code must be available
- Proprietary – typically restrict user rights and protect commercial interests of copyright owners
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Per-feature or tabular comparisons of licences and categorised lists
- Choose an open-source license, https://choosealicense.com/appendix/
- Joinup Licensing Assistant – Find and compare software licenses, https://joinup.ec.europa.eu/collection/eupl/solution/joinup-licensing-assistant/jla-find-and-compare-software-licenses
- DejaCode licence finder; it can filter by one or several categories, licence text and a few key characteristics
- All, https://enterprise.dejacode.com/licenses/
- Permissive, https://enterprise.dejacode.com/licenses/?sort=name&category=Permissive
- Weak copyleft, https://enterprise.dejacode.com/licenses/?sort=name&category=Copyleft+Limited
- Strong copyleft, https://enterprise.dejacode.com/licenses/?sort=name&category=Copyleft
- Wikipedia tables and classified lists
- GPL compatible licenses are listed in the 'GPL (v3) compatibility' column of the table in https://en.wikipedia.org/wiki/Comparison_of_free_and_open-source_software_licences#Approvals
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