What do some good books say about March 8, March 9 and April 9?

Practice for three days in winter and three days in summer.

The Song of Nineteen Nine in the Middle and Lower Reaches of the Yellow River: 1929 was not released; Walking on the 3949 River; 5969 see willows along the river; Seven or nine talks, eight or nine geese come; 1999 and 1999, cattle are being farmed everywhere.

Beijing version of the number nine (relatively common, widely promoted): 1929 does not shoot; Walking on the ice in 3949; 5969 see willows along the river; Seven or nine talks, eight or nine geese come; 1999 and 1999, cattle are being farmed everywhere.