BIRD STUDY / 
British Trust for Ornithology. 
 -- Tring [Gran Bretaña] :   BTO  
 - 195-?--  . -- 
<br/><br/>ISSN 0006-3657 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Ornitología
<br/><br/><label>Universal Decimal Class. No.: </label>598.2(05)