Litterature
- Buringh , P. 1960 . “ The application of aerial photographs in soil surveys ” . In Manual of Photographic Interpretation, American Soc. of Photogrammetry 633 – 666 . Washington , D. C.
- Vixk , A. P. A. 1962 . Practical soil surveys and their interpretation for practical purposes , Publications of the International Training Centre for Aerial Survey . Delft, — Series B, number 16