cleong110#21 used by SignBLEU. They say

We use the ELAN version of Boston University’s The National Center for Sign Language and Gesture Resources corpus (NCSLGR) (Neidle and Sclaroff, 2012)

Carol Neidle and Stan Sclaroff. 2012. National Center for Sign Language and Gesture Resources (NCSLGR) corpus. Boston University. ISLRN, American Sign Language Linguistic Research Project (ASLLRP), ISLRN 833-505-711564-4.

Which links to https://www.islrn.org/resources/833-505-711-564-4/, which links to https://www.bu.edu/asllrp/ncslgr.html as the source.

Currently we have an entry for NCSLGR, it goes to dataset:databases2007volumes, aka

Databases, NCSLGR. 2007. “Volumes 2–7.” American Sign Language Linguistic Research Project (Distributed on CD-ROM ….

and it's got some TODOs

https://www.bu.edu/asllrp/ncslgr-for-download/download-info.html