I think the notes I take, as illustrated on the screenshot above, are written in RTF and stored into DEVONthink. I’m not up to write an AppleScript, as suggested by Mark Anderson. I realized that when I tried, this afternoon, to adjust this script you probably know 
: http://forum.eastgate.com/t/script-to-export-certain-devonthink-metadata-in-a-tsv-for-tinderbox-import/1105 Let’s forge a key!