McCall, M. K., Martinez, J. and Verplanke, J. (2015) “Shifting Boundaries of Volunteered Geographic Information Systems and Modalities: Learning from PGIS”, ACME: An International Journal for Critical Geographies, 14(3), pp. 791–826. Available at: https://acme-journal.org/index.php/acme/article/view/1234 (Accessed: 23 April 2024).