On Monday, military officers from the ten-member Association of Southeast Asian Nations (ASEAN) boarded the carrier in Singapore and returned on Friday.
The two retailers have been identified as Lim Geok Kay of Teck Bee Brothers Company at 220 Syed Alwi Road and Chia Thuang Chiew of CPP Trading at Block 731 Yishun Street 72.
The study was carried out by an international group of researchers from Lawrence Livermore National Laboratory (LLNL) and Institut fur Planetologie at the University of Munster in Germany.