APA (7th ed.) Citation

Fix, G. M., Kim, B., Ruben, M. A., & McCullough, M. B. (2022). Direct observation methods: A practical guide for health researchers. Elsevier.

Chicago Style (17th ed.) Citation

Fix, Gemmae M., Bo Kim, Mollie A. Ruben, and Megan B. McCullough. Direct Observation Methods: A Practical Guide for Health Researchers. Elsevier, 2022.

MLA (9th ed.) Citation

Fix, Gemmae M., et al. Direct Observation Methods: A Practical Guide for Health Researchers. Elsevier, 2022.