1. Abbott, M., Romild, U., & Volberg, R. A. (2013). Gambling and problem gambling in Sweden: Changes between 1998 and 2009. Journal of Gambling Studies. doi: 10.1007/s10899-013-9396-3 . [Epub ahead of print].
2. Abbott, M., & Volberg, R. (1991). Gambling and problem gambling in New Zealand: Report on phase one of the national survey of problem gambling. Research Series No. 12. Wellington: New Zealand Department of Internal Affairs.
3. Abbott, M. W., Volberg, R. A., & Ronnberg, S. (2004). Comparing the New Zealand and Swedish national surveys of gambling and problem gambling. Journal of Gambling Studies, 20(3), 237–258.
4. American Association for Public Opinion Research (AAPOR) Cell Phone Task Force. (2010). Weighting in RDD cell phone surveys. In New considerations for survey researchers when planning and conducting RDD telephone surveys in the U.S. with respondents reached via cell phone numbers (pp. 61–76). Deerfield, IL: American Association for Public Opinion Research.
5. American Gaming Association. (2013). Gaming revenue: 10-year trend. http://www.americangaming.org .