Syahwir, I.D. et al. 2019. INTERNET OF THINGS OF ELECTRONIC SEAL BASE ON GPRS SHORT MESSAGE SERVICE AND THINGSPEAK. Spektra: Jurnal Fisika dan Aplikasinya. 4, 3 (Dec. 2019), 125–132. DOI:https://doi.org/10.21009/SPEKTRA.043.03.