J. David Muyskens

title	ISBN-13 (ISBN-10)	year of publication
Forty Days to a Closer Walk with God: The Practice of Centering Prayer	978-0-8358-9904-8 (0-8358-9904-7)	2007
Sacred Breath: 40 Days of Centering Prayer	978-0-8358-1031-9 (0-8358-1031-3)	2010