Information sources reporting on studies, but not actually citing and linking to those studies, apparently don’t want to help readers to learn more. Not citing and linking has created well-justified frustration. Sources that don’t provide relevant citations and links should be judged less credible. You should be suspicious of their motives. You should be offended by their lack of respect for your curiosity and your interest in learning.
Formal possibilities for generosity go far beyond citing and linking. Generosity means presenting information so that it is easier for others to use in their own ways. Presenting a table of data in a pdf file is mean. Presenting a table so that an application can access its data with understanding of its semantics is generous. Linking the table to a web-accessible version of the whole dataset from which the table was derived is very generous.