https://digital.library.lse.ac.uk/Documents/Detail/report-on-the-census-of-production-for-1976.-pa603-water-supply/438157
Report on the Census of Production for 1976. PA603 Water supply - LSE Digital Library
https://digital.library.lse.ac.uk/Documents/Detail/report-on-the-census-of-production-for-1979.-pa603-water-supply/443887
Report on the Census of Production for 1979. PA603 Water supply - LSE Digital Library
https://digital.library.lse.ac.uk/Documents/Detail/report-on-the-census-of-production-for-1977.-pa603-water-supply/440045
Report on the Census of Production for 1977. PA603 Water supply - LSE Digital Library