Jarzembowski 1990. Early Cretaceous zygopteroids of southern England, with the description of Cretacoenagrion alleni gen. nov., spec. nov. (Zygoptera: Coenagrionidae; 'Anisozygoptera': Tarsophlebiidae, Euthemistidae). Odonatologica, 19(1) 1990: 27-37