Source for acknowledgement:

Commentary on CSA Standard S37-01 Antennas, Towers and Antenna-Supporting Structures, Issue A February 2005.
prepared by: Robert B. Dryburgh P. Eng., Donald G. Marshall P. Eng., Albert (Ab) J. Nightingale P. Eng.
http://www.noeticholdings.com/commentary_on_csa_s37/