Here are some Technical Systems Consultants, Inc. manuals scanned by Joel Setton. Joel would like to know about any errors you find. You can contact him at:
6809 FLEX User's Manual (59 Pages PDF 110k)
6809 FLEX Programmer’s Manual (62 Pages PDF 144k)
6809 FLEX Adaptation Guide (103 Pages PDF 250k)
Sort / Merge User's Manual (71 Pages PDF 160k)
Extended BASIC User's Manual (88 Pages PDF 220k)
Additional FLEX software documentation can be found on the FLEX User Group site.