Sentence:  Scarcity of paper caused many Southerners to adopt the practice of cross writing , i. e. , after writing from left to right of the <WSD>page</WSD> in the usual manner , they gave the sheet a half turn and wrote from end to end across the lines previously written . 
Meaning of the word marked with <WSD> tags:  one side of one leaf (of a book or magazine or newspaper or letter etc.) or the written or pictorial matter it contains