jgg     2008 28 (1):  41-44    ISSN: 0412-1961  CN: 21-1139/TG UNBIASED ESTIMATION OF EXTENDED GREY MODEL AND ITS APPLICATION TO FORECAST OF DEFORMATION OF STEEP SLOPES Liu Zhiping ;and He Xiufeng Hohai University, Institute of Satellite Navigation & Spatial Information System, Nanjing 210098 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null