Adding, deleting, and referencing reference files in an instance.
Also, adding, deleting, and referencing reference URLs
For details, see "Reference file and reference URL processing"

　 1. Reference files and reference URLs in Lclass
　     Select an L class.
　 　Add, delete, or reference a reference file
　 　Also, add, delete, or reference a reference URL.
  　

　 2. Reference files and URLs in Sclass
　     Select S class.
　 　Add, delete, and reference reference files.
　 　Also, add, delete, and reference using reference URLs.