Analisis yuridis perlindungan konsumen pengguna jasa angkutan udara terhadap opsi asuransi perjalanan dalam pembelian tiket elektronik jasa angkutan udara Lion Air = juridical analysis on consumer protection of commercial aircraft passangers concerning the option of travel insurance in the purchase of electronic ticket of Lion Air - Elisabeth Saragionova Narotama Allaganio, author (2012)