- http://www.gamon.org/Profession/TCL/STkoutline.htm - an experimental fork of tkoutline 0.92. Some of the features of this fork are part of tkoutline 0.93
- http://www.theplaintruth.cjb.net/archives/000018.html - a blog entry from someone who likes tkoutline
- Treepad 1 - very nice, but not open-source. Freeware versions for both Windows and Linux. Shareware versions for Windows only, but Linux shareware version is in development.
- Woody 2 - written in python, curses based (console mode only)
- LEO 3 - outline based literate program editer. Cross-platform, written in python/Tk. This is a two-pane outliner
- Java Outline Editor 4 Nice-looking cross-platform Java outliner. Supports editing more than one outline at a time.
- Hierarchical Notebook - 5 Single-pane console outliner based on a curses interface.
- TVO: The Vim Outliner - 6 Outliner based on the vim text editor.
- KeyNote - 7 Open source, double-pane outliner with a long list of features. Windows only. Compatible with freeware Treepad files.
- Reviews of more than a dozen windows outliner programs can be found at http://john.redmood.com/organizers.html
- http://www.outliners.com. There is a nice discussion board about outliners here. Also, if you have a Macintosh, the More Outliner is availble for download.
- http://www.atpm.com/9.10/atpo.shtml - Incredibly comprehensive set of 3 (as of 12/6/03) articles surveying every conceivable outliner feature and outliner applications available for the Mac.