After a long trial and error phase in the nineties I found outliners to be the best of all tools for this purpose. I successfully worked with Netmanage Ecco for

After a long trial and error phase in the nineties I found outliners to be the best of all tools for this purpose. I successfully worked with Netmanage Ecco for about ten years and then wrote my own tool which also runs on Linux and features cross-links and other useful functions missing in Ecco. I even write specifications and do requirements management and status accounting with this tool. Here is the link: https://github.com/rochus-keller/CrossLine/ https://github.com/rochus-keller/CrossLine/