I found this site to be useful: http://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/transposons/integrons/integrons.html
citing: "Transposons have direct or indirect repeat sequences at their ends" and integrons "contained a site-specific integrase gene of the same family as those found in phage but lacked many gene products associated with transpositon." "Due to these differences, the elements were not grouped with transposons and were named integrons"
There are also some links to original research articles at the bottom.