PDScores is an Objective-C library based on Max Little's original MATLAB code, which is licensed under the Creative Commons Attribution-ShareAlike 3.0 license. Per the terms of that license, as a derivative work, this library is made available under the same license.
Applications that use this library (unmodified) are considered collections under the license, not adaptations, and thus are not subject to the ShareAlike terms requiring the use of the same license.