Whenever possible, it's a good idea to cite the original research evidence (as referenced within review databases like UpToDate and Cochrane Library). There are times, however, when you may want to cite the UpToDate or Cochrane summary. In that case, the citation formats below are recommended.
An example of a citation for an UpToDate review:
McCulloch, D. K., & Robertson, R. P. (2019). Pathogenesis of type 2 diabetes mellitus. UptoDate. Retrieved February 2, 2021,
An example of a citation for a Cochrane Library review:
Mehrholz, J., Pohl, M., Platz, T., Kugler, J., & Elsner, B. (2018). Electromechanical and robot-assisted arm training for improving activities of daily living, arm function, and arm muscle strength after stroke. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.CD006876.pub5
Citations from the Merck Manual follow the APA Publication Manual guidelines for an entry in an encyclopedia or reference work. Because the Merck Manual is updated regularly, a Retrieved date is also included to alert a reader that the information may have changed since it was retrieved.
Ortega, V. E., & Genese, F. (2019). Asthma. In Merck Manal Professional Version. Merck & Co., Inc. Retrieved February 18, 2021, from https://www.merckmanuals.com/professional/pulmonary-disorders/asthma-and-related-disorders/asthma