To address the problem of changing and nonworking URL’s, scholarly publishers are assigning a Digital Object Identifier (Opens in New Window) (DOI) to journal articles. The DOI is a unique and persistent link to the article.
The DOI is often listed in the item record in a database, in the article citation, or on the first page of the document. It may also be found through the publisher website.
Matamoros, V., Arias, C., Brix, H., & Bayona, J. (2007). Removal of pharmaceuticals and personal care products (PPCPs) from urban wastewater in a pilot vertical flow constructed wetland and a sand filter. Environmental Science & Technology, 41(23), 8171-8177. http://dx.doi.org/10.1021/es071594+
Baicker, K. (2006). The labor market effects of rising health insurance. Journal of Labor Economics, 24(3), 609-634. http://dx.doi.org/10.1086/505049
If no DOI is listed, use CrossRef free DOI lookup (Opens in New Window) to see if the article is assigned a DOI.
Note: If there is an & in the title, you may need to change the & to and.