| Source | URL |
| ISI Web of Knowledge | http://isiknowledge.com |
| IEEE Xplore Digital Library | http://ieeexplore.ieee.org |
| ACM Digital Library | http://dl.acm.org |
| SpringerLink | http://www.springerlink.com |
| Scopus | http://www.scopus.com |
| Scirus | http://www.scirus.com |
| ScienceDirect | http://www.sciencedirect.com |
| CiteSeerX | http://citeseer.ist.psu.edu |
| Pion Publications Ltd. | http://www.pion.co.uk |
| The DBLP Computer Science | http://www.informatik.uni-trier.de/~ley/db |
| WorldCat | http://firstsearch.oclc.org |
| Ingenta | http://www.ingentaconnect.com |
| Engineering Village | http://www.engineeringvillage2.org |
| The AutoCarto Archives | http://mapcontext.com/autocarto/proceedings |
| International Archives of the ISPRS | http://www.isprs.org/publications/archives.aspx |
| EBSCO Host | http://search.ebscohost.com |
| Google Scholar | http://scholar.google.es/ |