New Zealand: http://www.hpac.ca/pub/doc/NZaerotowManual.pdf (http://www.hpac.ca/pub/doc/NZaerotowManual.pdf)
Australia: http://www.hgfa.asn.au/resources/TowManualSep05.pdf (http://www.hgfa.asn.au/resources/TowManualSep05.pdf)
BHPA: http://www.bhpa.co.uk/pdf/BHPA_Tech_Manual.pdf (http://www.bhpa.co.uk/pdf/BHPA_Tech_Manual.pdf) (Section 2)
Canada
http://hpac.ca/tow/HPAC_Tow_Manual.asp (http://hpac.ca/tow/HPAC_Tow_Manual.asp)