ProQuest maintenance Sunday 30 September
ProQuest will be unavailable on Sunday 30 September
Due to system maintenance ProQuest products will be unavailable for 12 hours from 03.00 in the morning on Sunday 30 September.
Article text (excluding photos or graphics) available under an Attribution-NonCommercial-ShareAlike Creative Commons license.
Photos and graphics subject to third party copyright used with permission or © Imperial College London.