A way to link from an external page to the current Angel course and specific content within that course:
https://cms.psu.edu/section/content/default.asp?WCI=Goto&WCU=CRSCNT&preview=0&MATCH=some+search+string+separated+by+plus+signs
A way to link to associated files within a course:
$COURSE_PATH$_assoc/subdirectory/filename