Next3 Website NEXT3 Filesystem Home Page (sourceforge.net)
Next3 SourceForge NEXT3 download | SourceForge.net
LWN article [2]
Ted T'so rosting Next and explaining the conflict between NEXT3 and EXT4 [1]
NEXT provide snapshot to EXT3 while keeping the EXT3 base. Once the partition is converted to NEXT3 it will still be accessible to EXT3 system but in read only (set through a TAG).