Journal article (2009) - Nicholas H.M. Caldwell (author), C. A. McMahon (author), M. J. Darlington (author), Peter Heisig (author), D. M. Holburn (author), John Clarkson (author), P.J. Clarkson (author), P. J. Clarkson (author), P. John John Clarkson (author), P. John Clarkson (author), P.J. John Clarkson (author), P. Clarkson (author), John John Clarkson (author), P. J. John Clarkson (author), P. John Clarkson (author)