McMahon, Glenda Shaw, Rod Septic tank systems version 2 Septic tank systems version 2 WEDC;Technical;Diagram;Sanitation;Septic tanks;International and Development Communication 2019-05-02
    https://repository.lboro.ac.uk/articles/figure/Septic_tank_systems_version_2/8067860
10.17028/rd.lboro.8067860.v1