| 1999 | 2. Auflage. | Geb/SU, F:17x24 cm, 240 S, 24 Farbtafeln, Verbreitungskarten. | WG: Buch | Weltführer der Baumsegler (Hemiprocnidae) und Eigentlichen Segler (Apolidae). | The second edition of this highly acclimed monograph has been extensively revised to take account of recent information, and several plates have been revised by the artist. | [E] | | Helm Identification Guides