APA
Saffer H., Chaloupka F., . (1998). Demographic differentials in the demand for alcohol and illicit drugs. Cambridge, Mass: National Bureau Economic Research.
Chicago
Saffer Henry, Chaloupka Frank, . 1998. Demographic differentials in the demand for alcohol and illicit drugs. Cambridge, Mass: National Bureau Economic Research.
Harvard
Saffer H., Chaloupka F., . (1998). Demographic differentials in the demand for alcohol and illicit drugs. Cambridge, Mass: National Bureau Economic Research.
MLA
Saffer Henry, Chaloupka Frank, . Demographic differentials in the demand for alcohol and illicit drugs. Cambridge, Mass: National Bureau Economic Research. 1998.