Stock exchange practices : hearings before the Committee on Banking and currency United States Senate : seventy-third congress, first session on S. Res. 84 ,72d congress, a resolution to investigate practices of stock exchanges with respect to the buying and selling and the borrowing and lending of listed securities and S. Res. 56 ,73d congress, a resolution to investigate the matter of banking operations and practices, the issuance and sale of securities, and the trading therein