Sentence:  Very recently , observations have been made at 8 - mm wave length with a reflector 22 <WSD>meters</WSD> in diameter with a resultant beam width of only about 2 ' ( Amenitskii , Noskova , and Salomonovich , 1960 ) . 
Meaning of the word marked with <WSD> tags:  the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards)