Free, John Brand. <br/><br/>
Bumblebees / 
by John B. Free and Colin G. Butler ; with two appendices by Ian H.H. Yarrow. 
 - London :  Collins,  [1968] 
<br/><br/> First published 1959. 
<br/><br/>Bibliography: p. [190]-197. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Bumblebees.<br/>Hymenoptera -- Great Britain.--Hymenoptera -- Great Britain.