fortis, head and foot from lateral, underwing showing length of remiges
Philip Lutley Sclater (text)
1890
<i><a href="//commons.wikimedia.org/wiki/Catalogue_of_the_birds_in_the_British_Museum" title="Catalogue of the birds in the British Museum">Catalogue of the birds in the British Museum</a></i> (<a rel="nofollow" class="external text" href="https://archive.org/details/catalogueofbirds15brit">Vol. 15</a> Page 273)