1912=1912,31; 1913=1913,46; 1914/15=1914,43; 1915/16=1915,43; 1916/17=1916,43; 1917/18=1917,43; 1918/19=1918,36; 1919/20=1919,71; 1920/21=1920,33; 1921/22=1921,48; 1922/23=1922,50; 1924=1924,1; 1925=1925,1; 1926=1926,1; 1927=1927,1; 1928=1928,1; 1929=1929,1; 1935=1935,1; 1936=1936,1; 1937=1937,1; 1938=1938,1; 1939=1939,1 von:
USA. Bureau of Education: Bulletin / United States, Department of the Interior, Bureau of Education (SLUB)