N-spheres: regular black holes without apparent horizons, static wormholes with event horizons and gravastars with a tube-like core
https://www.powershow.com/view1/1fa261-ZDc1Z/N-spheres_regular_black_holes_without_apparent_horizons_static_wormholes_with_event_horizons_and_gravastars_with_a_tube-like_core_powerpoint_ppt_presentation
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