Fraser, Lt.-Col. F. C. (2009). "A Note on the Classification of Zacallites Balli Cockerell (Upper Eocene) (Order Odonata)". Proceedings of the Royal Entomological Society of London. Series B, Taxonomy. 9 (4): 62–64. doi:10.1111/j.1365-3113.1940.tb00346.x.
Bechly, Günter; Garrouste, Romain; Aase, Arvid; Karr, Jered A.; Grande, Lance; Nel, André (2020). "The damselfly palaeofauna from the Eocene of Wyoming and Colorado, USA (Insecta, Odonata, Zygoptera)". Papers in Palaeontology. 7 (3): 1373–1402. doi:10.1002/spp2.1346. S2CID229441628.
Archibald, S. B.; Cannings, R. A.; Erickson, R. J.; Bybee, S. M.; Mathewes, R. W. (2021). "The Cephalozygoptera, a new, extinct suborder of Odonata with new taxa from the early Eocene Okanagan Highlands, western North America". Zootaxa. 4934 (1): zootaxa.4934.1.1. doi:10.11646/zootaxa.4934.1.1. PMID33756770. S2CID232337536.
nih.gov
pubmed.ncbi.nlm.nih.gov
Archibald, S. B.; Cannings, R. A.; Erickson, R. J.; Bybee, S. M.; Mathewes, R. W. (2021). "The Cephalozygoptera, a new, extinct suborder of Odonata with new taxa from the early Eocene Okanagan Highlands, western North America". Zootaxa. 4934 (1): zootaxa.4934.1.1. doi:10.11646/zootaxa.4934.1.1. PMID33756770. S2CID232337536.
Bechly, Günter; Garrouste, Romain; Aase, Arvid; Karr, Jered A.; Grande, Lance; Nel, André (2020). "The damselfly palaeofauna from the Eocene of Wyoming and Colorado, USA (Insecta, Odonata, Zygoptera)". Papers in Palaeontology. 7 (3): 1373–1402. doi:10.1002/spp2.1346. S2CID229441628.
Archibald, S. B.; Cannings, R. A.; Erickson, R. J.; Bybee, S. M.; Mathewes, R. W. (2021). "The Cephalozygoptera, a new, extinct suborder of Odonata with new taxa from the early Eocene Okanagan Highlands, western North America". Zootaxa. 4934 (1): zootaxa.4934.1.1. doi:10.11646/zootaxa.4934.1.1. PMID33756770. S2CID232337536.