You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Hierarchical Aggregation for Information Visualization: Overview, Techniques, and Design Guidelines 
Chapter Title:  Discriminability (G4) 
1. Abstract of Cited Paper (BIB001):  We present CiteWiz, an extensible framework for visualization of scientific citation networks. The system is based on a taxonomy of citation database usage for researchers, and provides a timeline visualization for overviews and an influence visualization for detailed views. The timeline displays the general chronology and importance of authors and articles in a citation database, whereas the influence visualization is implemented using the Growing Polygons technique, suitably modified to the context of browsing citation data. Using the latter technique, hierarchies of articles with potentially very long citation chains can be graphically represented. The visualization is augmented with mechanisms for parent-child visualization and suitable interaction techniques for interacting with the view hierarchy and the individual articles in the dataset. We also provide an interactive concept map for keywords and co-authorship using a basic force-directed graph layout scheme. A formal user study indicates that CiteWiz is significantly more efficient than traditional database interfaces for high-level analysis tasks relating to influence and overviews, and equally efficient for low-level tasks such as finding a paper and correlating bibliographical data.

Literature Review:
Principle. Design visual aggregates to be easily distinguishable from visual data items. Discussion. Visual aggregates and visual data items must be easy to differentiate in order to not convey the wrong information to the viewer. While using the same visual representation for both aggregates as for items is often easiest, it may give the viewer the wrong idea about the data. For example, the aggregate of two points in a scatterplot might be a single point, or the aggregate of two polylines in a parallel coordinate display might be a single polyline on their average BIB001 . A better choice is to introduce a novel representation for the visual aggregate, or to decorate the aggregate with some extra graphical feature, like the shadows for the growing polygons technique BIB002 (Fig. 13) .