Data Sources 



BioSciences Information Service, Biological Abstracts. Philadelphia, 



Pennsylvania. 

 Commonwealth Agricultural Bureau, Plant Breeding Abstracts. Farnham 



Royal, United Kingdom. 

 Commonwealth Bureau of Dairy Science and Technology, Dairy Science 



Abstracts. Shinfield, Reading, United Kingdom. 

 Commonwealth Bureau of Pastures and Field Crops, Field Crops 



Abstracts. Aberystwyth, Wales. 

 Food and Agricultural Organization of the United Nations, Production 



Yearbook. Rome, Italy. 

 Indian National Scientific Documentation Center, Indian Science 



Abstracts. Delhi, India. 

 International Institute of Agriculture, International Yearbook of Agricul- 

 tural Statistics. Rome, Italy, 1912-47. 



201 



