Documentation for ARToolkitPlus

the old ARToolkitPlus website gives a rough overview over the additional features:
http://studierstube.icg.tu-graz.ac.at/handheld_ar/artoolkitplus.php

the ARToolkit documentation gives a nice overview about how the library works and how to use it. The API mention there does not match though.
http://www.hitl.washington.edu/artoolkit/documentation/index.html

a publication regarding ARToolkitPlus explains the specific additions in detail:
http://www.icg.tugraz.at/Members/daniel/Publications/ARToolKitPlusMobilePoseTracking.pdf/at_download/file