Ha, N. V. (2012) “The description of two new species Helicometra pisodonophi sp. n. and Opecoelus haduyngoi sp. n. (Trematoda: Opecoelidae) from marine fishes in Ha Long bay, Vietnam”, Academia Journal of Biology, 34(2), pp. 133–138. doi: 10.15625/0866-7160/v34n2.949.