Opinions from E. N. Kurochkin 2000
- 'Alexornis belongs to Alexornithidae'
- 'Alexornithidae belongs to Alexornithiformes'
- 'Alexornithiformes belongs to Enantiornithes'
- 'Ambiortidae belongs to Ambiortiformes'
- 'Ambiortiformes belongs to Palaeognathae'
- 'Ambiortus belongs to Ambiortidae'
- 'Ambiortus dementjevi belongs to Ambiortus' according to Kurochkin 1982
- 'Ambiortus dementjevi belongs to Ambiortus'
- 'Anseriformes belongs to Neognathae'
- 'Asiahesperornis belongs to Asiahesperornithinae'
- 'Asiahesperornis bazhanovi belongs to Asiahesperornis'
- 'Asiahesperornithinae belongs to Hesperornithidae'
- 'Avisauridae belongs to Alexornithiformes'
- 'Avisaurus belongs to Avisauridae'
- 'Baptornis belongs to Baptornithidae'
- 'Baptornithidae belongs to Hesperornithiformes'
- 'Enantiornis belongs to Avisauridae'
- 'Enantiornis leali belongs to Enantiornis'
- 'Enantiornis martini belongs to Enantiornis'
- 'Enantiornis walkeri belongs to Enantiornis'
- 'Enantiornithes was reranked as a infraclass and belongs to Sauriurae'
- 'Enantiornithidae belongs to Alexornithiformes'
- 'Fregatidae belongs to Pelecaniformes'
- 'Gobipteryx belongs to Alexornithidae'
- 'Gobipteryx minuta belongs to Gobipteryx'
- 'Gruiformes belongs to Neognathae'
- 'Gurilynia belongs to Enantiornithidae'
- 'Gurilynia nessovi belongs to Gurilynia'
- 'Hesperornidae is corrected as Hesperornithidae and belongs to Hesperornithiformes'
- 'Hesperornis belongs to Hesperornithidae'
- 'Hesperornis gracilis belongs to Hesperornis'
- 'Hesperornis regalis belongs to Hesperornis'
- 'Hesperornis rossica is corrected as Hesperornis rossicus and belongs to Hesperornis'
- 'Hesperornithiformes belongs to Odontornithes'
- 'Horezmavis belongs to Gruiformes'
- 'Horezmavis eocretacea belongs to Horezmavis'
- 'Ichthyornis maltshevskyi is recombined as Lenesornis maltshevskyi'
- 'Judinornis belongs to Baptornithidae'
- 'Judinornis nogontsavensis belongs to Judinornis'
- 'Kizylkumavis belongs to Alexornithidae'
- 'Kizylkumavis cretacea belongs to Kizylkumavis'
- 'Kuszholia belongs to Kuszholiidae'
- 'Kuszholia mengi belongs to Kuszholia'
- 'Kuszholiidae belongs to Aves'
- 'Lenesornis belongs to Alexornithidae'
- 'Lestornis crassipes is recombined as Hesperornis crassipes'
- 'Limnofregatinae belongs to Fregatidae'
- 'Mononychus olecranus is recombined as Mononykus olecranus'
- 'Mononykus belongs to Parvicursoridae'
- 'Nanantius belongs to Alexornithidae'
- 'Nanantius valifanovi belongs to Nanantius'
- 'Neognathae belongs to Neornithes'
- 'Neornithes was reranked as a infraclass and belongs to Ornithurae'
- 'Neuquenornis belongs to Alexornithidae'
- 'Odontornithes was reranked as a infraclass and belongs to Ornithurae'
- 'Ornithurae belongs to Aves'
- 'Otogornis belongs to Ambiortidae'
- 'Otogornis genghisi belongs to Otogornis' according to L. Hou 1994
- 'Otogornis genghisi belongs to Otogornis'
- 'Palaeognathae belongs to Neornithes'
- 'Parvicursor belongs to Parvicursoridae'
- 'Parvicursor remotus belongs to Parvicursor'
- 'Parvicursoridae belongs to Maniraptora'
- 'Pelecaniformes belongs to Neognathae'
- 'Platanavis belongs to Aves'
- 'Platanavis nana belongs to Platanavis' according to Nessov 1992
- 'Platanavis nana belongs to Platanavis'
- 'Praeornis belongs to Praeornithidae'
- 'Praeornis sharovi belongs to Praeornis' according to Rautian 1978
- 'Praeornis sharovi belongs to Praeornis'
- 'Praeornithes belongs to Aves'
- 'Praeornithidae belongs to Praeornithiformes'
- 'Praeornithiformes belongs to Praeornithes'
- 'Presbyornithidae belongs to Anseriformes'
- 'Sauriurae belongs to Aves'
- 'Sazavis belongs to Alexornithidae'
- 'Sazavis prisca belongs to Sazavis'
- 'Soroavisaurus belongs to Avisauridae'
- 'Volgavis belongs to Limnofregatinae'
- 'Volgavis marina belongs to Volgavis'
- 'Zhyraornis belongs to Alexornithidae'
- 'Zhyraornis kashkarovi belongs to Zhyraornis'
- 'Zhyraornis logunovi belongs to Zhyraornis'