Botting, Douglas.
Humboldt and the cosmos /
Douglas Botting 
. - New York : Harper & Row, Publishers,  1973 
. - 295 p.  ill.  27 cm. 
<br/>К.: Бібліогр. : c. 285-286, Index 
<br/><label>  ISBN: </label>06-010412-0 
<br/><br/><label>Subjects--Personal Names: </label><br/>Humboldt, Alexander von 1769-1859