van Amsterdam, J., Phillips, L., Henderson, G., Bell, J., Bowden-Jones, O., Hammersley, R., Ramsey, J., Taylor, P., Dale-Perera, A., Melichar, J., van den Brink, W., & Nutt, D. (2015). Ranking the harm of non-medically used prescription opioids in the UK. Regulatory toxicology and pharmacology : RTP, 73(3), 999-1004. https://doi.org/10.1016/j.yrtph.2015.09.014