Another book (details below), written in German has just been published and is available from Amazon at
It is expensive – priced at $87.00 – and has 144 pages. More than that I cannot say as I have not seen it, but I will be very interested to receive any comments or information about this book which I can pass on.
Schwarzenbacher, S. (2009) Konduktiv mehrfach- therapeutische Förderung nach Petö und Keil: Theorie – Praxis – Effektivität. VDM-Verlag. ISBN-10: 3639206614 ISBN-13: 978-3639206616