Bretteville-Jensen, Anne L, Hans O Melberg and Andrew M Jones. "Sequential Patterns of Drug Use Initiation - Can We Believe In the Gateway Theory?" The B.E. Journal of Economic Analysis & Policy, 8.2 (2008): -. Retrieved 21 May. 2013, from doi:10.2202/1935-1682.1846

Bretteville-Jensen, A., Melberg, H. & Jones, A. (2008). Sequential Patterns of Drug Use Initiation - Can We Believe In the Gateway Theory?. The B.E. Journal of Economic Analysis & Policy, 8(2), pp. -. Retrieved 21 May. 2013, from doi:10.2202/1935-1682.1846

Bretteville-Jensen, Anne L, Hans O Melberg and Andrew M Jones. 2008. Sequential Patterns of Drug Use Initiation - Can We Believe In the Gateway Theory?. The B.E. Journal of Economic Analysis & Policy. 8(2): -. Retrieved 21 May. 2013, from doi:10.2202/1935-1682.1846