561.13
Erd
I
Erdtman , Gunnar , 1897 - 
An introduction to pollen analysis .
Foreword by Roger P. Wodehouse . New York , The Ronald Press ( c 1943) 
239p.ilus. 25  cm. ( Chronica Botanica New Series of Plants Science Books , vol. 12 ) 
Bibliografía al final de los capitulos .