...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Most of the internal implementation of red-black trees is based on that of SGI STL stl_tree.h file:
Copyright (c) 1996,1997 Silicon Graphics Computer Systems, Inc. Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. Silicon Graphics makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.
Copyright (c) 1994 Hewlett-Packard Company Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. Hewlett-Packard Company makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.
The tree destruction algorithm is based on Julienne Walker and The EC Team code:
This code is in the public domain. Anyone may use it or change it in any way that they see fit. The author assumes no responsibility for damages incurred through use of the original code or any variations thereof.
It is requested, but not required, that due credit is given to the original author and anyone who has modified the code through a header comment, such as this one.