Reichle, R. H., R. D. Koster, G. J. M. De Lannoy, B. A. Forman, Q. Liu, S. P. P. Mahanama, and A. Toure (2011), Assessment and enhancement of MERRA land surface hydrology estimates, Journal of Climate, 24, 6322-6338, doi:10.1175/JCLI-D-10-05033.1.
Reichle, R. H., 2012: The MERRA-Land Data Product. GMAO Office Note No. 3 (Version 1.2), 38 pp, available at http://gmao.gsfc.nasa.gov/pubs/office_notes.
Reichle, R. H. and Coauthors (2011b), GMAO Research Highlights: The MERRA-Land data product, available at http://gmao.gsfc.nasa.gov/research/landsurface/highlights/GMAO_2011Highlights_Reichle_et_al_MERRA-Land.pdf
Please acknowledge use of MERRA-Land data as outlined here.