@article{PetBuh14, title = {Identifiability of {G}aussian Structural Equation Models with Equal Error Variances}, author = {Peters, J. and B{\"u}hlman, P.}, journal = {Biometrika}, volume = {101}, number = {1}, pages = {219--228}, year = {2014}, doi = {10.1093/biomet/ast043} }