Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Carl Wunsch and Patrick Heimbach,Practical global oceanic state estimation,Physica D: Nonlinear Phenomena,0167-2789,Elsevier BV,2007-06,230,1-2,197-208,https://cir.nii.ac.jp/crid/1360011142940942976,https://doi.org/10.1016/j.physd.2006.09.040