Intergovernmental Panel on Climate Change (IPCC). Report of the First Session of the WMO/UNEP Intergovernmental Panel on Climate Change (IPCC), text, 1989; (https://digital.library.unt.edu/ark:/67531/metadc11887/m1/2/: accessed April 22, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .