Certainly not a new problem (this paper is from 1982, so old that my University subscription doesn't cover it). This might be a better link to start such a disc

Certainly not a new problem (this paper is from 1982, so old that my University subscription doesn't cover it). This might be a better link to start such a discussion: http://jrs.sagepub.com/content/99/4/178.long http://jrs.sagepub.com/content/99/4/178.long