Struktur komunitas gastropoda dan studi populasi cerithidea obtusa (lamark 1822) di hutan mangrove Pangkal Baru, Kabupaten Tanjung Jabung Baat, Jambi = The structure of Gastropods community and population study of Cerithidea obtusa (Lamarck 1822) in Mangrove forest Pangkal Babu, The District of Tanjung Jabung Barat, Jambi - Rusnaningsih, author (2012)