Hartlaub, Cl. (1904). Zoologie: Hydroiden. Résultats du Voyage du S.Y. Belgica en 1897-1898-1899 sous le commandement de A. de Gerlache de Gomery: Rapports Scientifiques (1901-1913). Buschmann: Anvers. 19, IV plates pp., more
Hartlaub, Cl. (1912). Reports on the results of dredging under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78), in the Caribbean Sea (1878-79), and along the Atlantic Coast of the United States (1880), by the US Coast Survey Steamer Blake: XLV. Die Comatuliden. Mem. Mus. Comp. Zool. XXVII(4): 1-491, 18 plates, more
Hartlaub, Cl. (1896). Beiträge zur Meeresfauna von Helgoland. IV. Die Coelenteraten Helgolands. Vorläufiger Bericht. Wiss. Meeresunters. N.F. Erster Band(I): 161-206, more