ResearchGate and Academia.edu are businesses that host open access research. They are neither publisher nor a journal. They are popular hubs on the web for sharing academic publications. There is no editorial review board, nor do they require articles be peer reviewed, although they may be. Since they are an academic social network with no provision for vetting the articles, evaluate each source carefully. If you choose to use an article found on ResearchGate or Academia.edu, cite it using the citation information provided by the authors. No mention of ResearchGate or Academia.edu is necessary.
Sources: Guide from the University of Michigan and the ResearchGate & Academia.edu websites.
