Ishihara, M., Harel, D., Levis, B., Levis, A. W., Riehm, K. E., Saadat, N., Azar, M., Rice, D. B., Sanchez, T. A., Chiovitti, M. J., Cuijpers, P., Gilbody, S., Ioannidis, J. P. A., Kloda, L. A., McMillan, D., Patten, S. B., Shrier, I., Arroll, B., Bombardier, C. H., Butterworth, P., Carter, G., Clover, K., Conwell, Y., Goodyear‐Smith, F., Greeno, C. G., Hambridge, J., Harrison, P. A., Hudson, M., Jetté, N., Kiely, K. M., McGuire, A., Pence, B. W., Rooney, A. G., Sidebottom, A., Simning, A., Turner, A., White, J., Whooley, M. A., Winkley, K., Benedetti, A., & Thombs, B. D. (2019). shortening self‐report mental health symptom measures through optimal test assembly methods: Development and validation of the Patient Health Questionnaire‐Depression‐4. Depression and anxiety, 36(1), 82–92. http://access.bl.uk/ark:/81055/vdc_100076779145.0x000022