Perlindungan debitur terhadap eksekusi jaminan fidusia dalam akad Murabahah : studi kasus Putusan Pengadilan Negeri Kisaran Nomor 23/Pdt.Sus-BPSK/2015/PN Kis = Legal protection against fiduciary guarantee execution in Murabahah cases : case study decision of District Court range Number 23/Pdt.Sus-BPSK /2015/PN Kis