Each article has a DOI (Digital Object Identifier) which may be used as a permanent URL to the article's abstract record (and the associated fulltext PDF). Navigate to the article abstracts and look for the "DOI" which appears just above the abstract field. This number will form a permanent URL to the article.
Example: http://doi.acm.org/10.1145/1132960.1132962
Be sure to prefix with the "proxy prefix"