Die 7 Hürden des ErfolgsDavid M. R. Covey, Stephan M. Mardyks, Andreas Schieberle · First published 2022Open the Tome
Leading in EnglishD. Vincent Varallo, Joerg Schmitz, Stephan M. Mardyks · First published 2017Open the Tome
Trap TalesDavid M. R. Covey, Stephan M. Mardyks, Andreas Schieberle · First published 2017Open the Tome
