The Westminster Confession, published in 1643, with the Ecumenical creeds and the Larger Catechism.
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The GPL 3 is a strong copyleft license, meaning that any copy or modification of this code must also be released under the GPL v3. In other words, you can take this code, add to it or make changes, then distribute your version. However, your version is subject to the same license requirements, meaning that it must be under GPL v3 as well, and that anyone can see your modified code and install it for their own purposes.
https://play.google.com/store/apps/details?id=org.armstrong.ika.westminster_confession