| Courtesy of Sarah Wigglesworth, granddaughter of Herbert Hardy Wigglesworth | Information sent to David Walker | | Personal information from Sarah Wigglesworth. |
| Professor David M Walker personal archive | Professor David M Walker, notes and collection of archive material | | Personal information from: Mrs AGR Mackenzie; John G Marr; Ian G Lindsay; Robert W R Mackenzie (of Perth); Mrs Isobel Adams(nee Gordon), Broughty Ferry ('Dr Marshall Mackenzie's quine'); David Stokes (interview with Charles McKean on 17 December 1985) |