This library [initially] used some [piece of] implementations
(may include codes) from these open source projects/resources:

1. Initial Affine Transforms
The original glm repo (g-truc), url: https://github.com/g-truc/glm

LICENSE[S]:
  The Happy Bunny License (Modified MIT License)
  The MIT License
  Copyright (c) 2005 - 2016 G-Truc Creation

FULL LICENSE: https://github.com/g-truc/glm/blob/master/copying.txt

2. Initial Quaternions
Anton's OpenGL 4 Tutorials book source code:

LICENSE:
  OpenGL 4 Example Code.
  Accompanies written series "Anton's OpenGL 4 Tutorials"
  Email: anton at antongerdelan dot net
  First version 27 Jan 2014
  Copyright Dr Anton Gerdelan, Trinity College Dublin, Ireland.

3. Euler Angles
  David Eberly
  Geometric Tools, LLC http://www.geometrictools.com/
  Copyright (c) 1998-2016. All Rights Reserved.

  Computing Euler angles from a rotation matrix (euler.pdf)
  Gregory G. Slabaugh

4. Extracting Planes
Fast Extraction of Viewing Frustum Planes from the World-View-Projection Matrix
Authors:
  Gil Gribb (ggribb@ravensoft.com)
  Klaus Hartmann (k_hartmann@osnabrueck.netsurf.de)

5. Transform AABB
Transform Axis Aligned Bounding Boxes:
http://dev.theomader.com/transform-bounding-boxes/
https://github.com/erich666/GraphicsGems/blob/master/gems/TransBox.c

6. Cull frustum
http://www.txutxi.com/?p=584
http://old.cescg.org/CESCG-2002/DSykoraJJelinek/

7. Quaternions
Initial mat4_quat is borrowed from Apple's simd library

8. Vector Rotation using Quaternion
https://gamedev.stackexchange.com/questions/28395/rotating-vector3-by-a-quaternion

9. Sphere AABB intersect
https://github.com/erich666/GraphicsGems/blob/master/gems/BoxSphere.c

10. Horizontal add
https://stackoverflow.com/questions/6996764/fastest-way-to-do-horizontal-float-vector-sum-on-x86

11. de casteljau implementation and comments
https://forums.khronos.org/showthread.php/10264-Animations-in-1-4-1-release-notes-revision-A/page2?highlight=bezier
https://forums.khronos.org/showthread.php/10644-Animation-Bezier-interpolation
https://forums.khronos.org/showthread.php/10387-2D-Tangents-in-Bezier-Splines?p=34164&viewfull=1#post34164
https://forums.khronos.org/showthread.php/10651-Animation-TCB-Spline-Interpolation-in-COLLADA?highlight=bezier

12. vec2 cross product
http://allenchou.net/2013/07/cross-product-of-2d-vectors/

13. Ken Shoemake's algorithm Implementation and Euler
Ken Shoemake's algorithm impl. is taken from this repo by permission:
  https://github.com/erich666/GraphicsGems/blob/master/gemsiv/euler_angle

* -------------------------- GraphicsGems EULA ----------------------------- *
|   http://www.realtimerendering.com/resources/GraphicsGems/                 |
|                                                                            |
| EULA: The Graphics Gems code is copyright-protected. In other words, you   |
| cannot claim the text of the code as your own and resell it. Using the     |
| code is permitted in any program, product, or library, non-commercial or   |
| commercial. Giving credit is not required, though is a nice gesture.       |
| The code comes as-is, and if there are any flaws or problems with any Gems |
| code, nobody involved with Gems - authors, editors, publishers, or         |
| webmasters - are to be held responsible. Basically, don't be a jerk, and   |
| remember that anything free comes with no guarantee.                       |
* -------------------------------- END --------------------------------------*/