Sentence:  In March , 1961 , representatives of the national laboratories of Australia , Canada , The Netherlands , United Kingdom , U. S. S. R. , United States , and West Germany , met at the NBS to devise means for reaching international agreement on a temperature <WSD>scale</WSD> between 10 and 90 * * f . 
Meaning of the word marked with <WSD> tags:  an ordered reference standard