The unit/sig->unit procedure is documented in v200alpha12: http://download.plt-scheme.org/doc/200alpha12/html/mzlib/mzlib-Z-H-32.html#%_sec_32.9 but does not appear to exist in collects/mzlib/unitsig.ss in v200alpha14. Is it gone for good, or did it just fall through the cracks? If it is gone, is there some other way to use a signed unit with unsigned units? --Doug