Andrew Morton: Ext3 for Linux 2.4 Kernel
   Provides links to documentation, patches, downloads, tools, CVS and mailing lists.
   http://www.zip.com.au/~akpm/linux/ext3/

IBM developerWorks: JFS Project
   Provides specifications, documentation and downloads for implementation with the Linux kernel.
   http://oss.software.ibm.com/developerworks/opensource/jfs/

John's Spec of the Second Extended Filesystem (ext2fs)
   File structure compiled from resources published on the Internet, personal experience and Linux source code.
   http://uranus.it.swin.edu.au/~jn/explore2fs/es2fs.htm

Simple Software Solutions: e_Fs
   Provides description of features and links. Links include scenarios for use and list of efs function calls to replace standard C functions.
   http://www.simple-sw.com/efsinfo.htm