1. Connectivity in Multi-factor Designs;Butz,1982
2. Loops, the free treatment group and a solution to the connectivity problem for three factor designs;Dodge,1988
3. Spanning sets for estimable contrast in classification models;Dodge;Ann. Statist.,1976
4. Connectedness and orthogonality in multi-factor designs;Eccleston;Biometrika,1975
5. On a new graphical method for determining the connectedness in three dimensional designs;Ghosh;Sankya B,1989