2014-01-08:
On page 29, in the formula for A_Delta(t), there is a minus (-) missing
in front of the first term in the inner block. Instead of
A_Delta(t) = 1/2 * ( t^2 * ( s1y s2x + s1x s2y + s1y s3x ...
It should read:
A_Delta(t) = 1/2 * ( t^2 * ( - s1y s2x + s1x s2y + s1y s3x ...
^^^
Thanks to David Geier.