Botting, Douglas. <br/><br/>
Humboldt  and the cosmos / 
Douglas Botting. 
 - London :  Michael Joseph,  1973. 
 - 295 p. :  ill. ;  26 cm. 
<br/><br/>Bibliography : p. 185-186. 
<br/><br/><label>ISBN: </label>0718111370 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Scientific expeditions.<br/>Botany.<br/>Zoology.