Dear Biomch-L readers,

Last year February and March, there was an extensive debate between, a.o.,
Ed Grood and myself on the pro's and con's of Cardanic angles as mechanized
in the Grood & Suntay `joint coordinate system', and the so-called `helical
angles' as proposed by myself.

During last week's second Mathematics in Orthopaedics symposium at the
Oskar-Helene-Heim at the Free University in Berlin, I was told that a mr(s)
Volkmann in Germany described this convention about one century ago.
Unfortunately, I have up to now been unable to locate a reference, and I
would be grateful for any help from the readership.

Thanks in advance -- Herman J. Woltring, Eindhoven/NL