Anchors in the r-model

In some other reference models (including the Dexter Model, the Model by Lange and the Tower Model) anchors have been identified as separ atable components of a hyperdocument. The presentation of the buttons for (source) anchors is specified in the concrete context level. Both the form of the display and also its position are described in the concrete content. Issues involving positioning of the target content's display when a link is followed are addressed in the definition of the concrete windows (in the concrete hypertext level).