Analisis usaha penjaminan kontra Bank garansi ditinjau dari hukum perjanjian Indonesia (Studi Kasus Perjanjian Penjaminan Bank Garansi Antara PT Jamkrindo dengan PT Bank X) = Analysis of Counter Bank Guarantee Business Judging from Indonesian Agreement Law (Case Study of Counter Bank Guarantee Agreement Between PT Jamkrindo and PT Bank X)