1. Abad, M. F. (2009). Financial aspects of open access journals. Contributions to Science, 5, 107–114.
2. Aguzzi, A. (2015). Scientific publishing in the times of open access. Swiss Medical Weekly, 145, w14118.
3. Akhtar, J. (2015). Issue of open access and predatory journals. Journal of the College of Physicians and Surgeons-Pakistan, 25(5), 313–314.
4. Antelman, K. (2004). Do open-access articles have a greater research impact? College & Research Libraries, 65(5), 372–382.
5. Archambault, É., Côté, G., Struck, B., & Voorons, M. (2016). Research impact of paywalled versus open access papers. 1science/Science-Metrix Report.
http://www.1science.com/PDF/oaNumber_OACA_3million_paper.pdf
.