doi dblpOn VR Spatial Query for Dual Entangled WorldsShao-Heng Ko | Ying-Chun Lin | Hsu-Chao Lai | Wang-Chien Lee | De-Nian YangProceedings of the 28th ACM International Conference on Information and Knowledge Management, CIKM 2019, Beijing, China, November 3-7, 2019