jgg     2009 29 (3):  128-130    ISSN: 0412-1961  CN: 21-1139/TG DEDUCTION OF BESSEL MEAN SQUARE ERROR FORMULA Deng Yonghe Architecture Department,Lishui College,Lishui 323000 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null