@article{de2010,
author = {de Haan. E. and Duckworth, A.},
title = {The holy grail of executive coaching: Discovering what really works.},
journal = {The OMC Coach and Mentor Journal},
year = {2010},
language = {English},
url = {www.ashridge.org.uk/Media-Library/Ashridge/PDFs/Publications/TheHolyGrailOfExecutiveCoaching.pdf}
}