https://www.concrete5.org/documentation/developers/5.6/files/grouping-files-with-sets
http://www.concrete5.org/documentation/developers/5.6/files/searching-and/
http://www.concrete5.org/documentation/developers/5.6/files/files-and-file-versions/
http://www.concrete5.org/documentation/developers/5.6/files/helpers/
http://www.frescojs.com/