1. Ein Beitrag zur Fehlerberechnung bei weinige Beobachtungen;Behrens;Landw. Jb.,1929
2. The information available in small samples;Bartlett;Proc. Camb. Phil. Soc.,1936
3. On Fisher and Behrens' test of significance for the difference in means of two normal samples;Sukhatme;Sankhyä,1938
4. The probable error of a mean;Student;Biometrika,1908
5. New tables for testing the significance of observations;Student;Metron,1925