@Misc{Jarvis2008,
author="Jarvis, A., H.I. Reuter, A. Nelson, E. Guevara",
title="Hole-filled SRTM for the globe Version 4, available from the CGIAR-CSI SRTM 90m Database",
year="2008",
url="http://srtm.csi.cgiar.org"
}