Looking for open access scientific journals for your reference? Check out PNAS!
PNAS is one of the world's most-cited and comprehensive multidisciplinary scientific journals, publishing more than 3,100 research papers annually. Established in 1914, PNAS publishes cutting-edge research, science news, Commentaries, Reviews, Perspectives, Colloquium Papers, and actions of the National Academy of Sciences.
Check out www.pnas.org for more information.