Network model of research papers on Ebola. Each node represents one paper of the 20% most cited papers on Ebola, and the edges represent the citations between the documents. The shape of the nodes indicates to which cluster (research front) they belong. The color of the nodes is according to a continuous scale from red to blue. This scale is a function of the clinical terms rate, so a red node could be considered a basic research paper, a purple one translational research, and a blue node is a clinical observation article.