Die vögel der paläarktischen fauna : vol. I
The author aims to describe the geographical variety of birds and categorizes them systematically.
Systematics
Die vögel der paläarktischen fauna : nachtrag I
The following pages are an addition to the works of that, the author wrote down previously. According to him It includes only the most important things like the new described forms and the geographical distribution.
Dr H. G. Bronn's klassen und ordnungen des thier-reichs
The author describes that with the help of his international colleagues and his role as a curator of an ornithological collection he wrote this publication about the systematics of birds.