1. Apache solr. http://lucene.apache.org/solr/. The Apache Software Foundation.
2. Apache spark. http://spark.apache.org/. The Apache Software Foundation.
3. D3.js. http://d3js.org/. Mike Bostock.
4. Eigenfactor.org. http://eigenfactor.org/. Eigenfactor.org.
5. Google scholar. https://scholar.google.com/. Google.