a link to the publisher. If available the doi ( digital object identifier) of the paper is used, in those cases the link is marked as {doi:...}. If no doi is available, these links are marked as {->Publisher}.
a link to the CBM document management, marked {->CBM DMS}. In the CBM DMS you'll find also meta data, especially in case of conference proceedings the name of the conference and the link to the associated presentation (in the Comments field).