TCHANGALOVA, N.; STILWELL, F. Search Engines and Beyond: A Toolkit for Finding Free Online Resources for Science, Technology and Engineering. Issues in Science and Technology Librarianship, [S. l.], n. 69, 2012. DOI: 10.5062/F4D21VHZ. Disponível em: https://journals.library.ualberta.ca/istl/index.php/istl/article/view/1554. Acesso em: 13 jun. 2021.