1109/100.486658">IEEE Robotics & Automation magazine (Volume 3, Issue 1, March 1996)</a>.

Since that time it has been periodically updated, most often, to accomodate changes to the Matlab language. The biggest such change was the introduction of Matlab objects which made the representation of quaternions, robots and links much more convenient. More recently the toolbox was updated to handle modified DH (Craig) as well as standard DH notation.
A more recent article
<a href="http://dx.doi.org/10.1109/MRA.200