Contributions to the osteology of birds. Part 1. Steganopodes. 1898. Contributions to the osteology of birds. Part 2. Impennes. 1898. Contributions to the osteology of birds. Part 4. Pygopodes. 1899. Contributions to the osteology of birds. Part 6. Cuculiformes. 1903. Contributions to the osteology of birds. Part 9. Tyranni; Hirundines; Muscicapa; Lanii and Gymnorhines. 1907.