@Article{ MARTINEZ_AZNAR:197-250,

author = { ANTONIO MARTINEZ CEGARRA and ENRIQUE RAFAEL AZNAR GARCÍA } ,

title = { An exact sequence in the first variable for torsor cohomology: the 2-dimensional theory of obstructions },

journal = { Journal of Pure and Applied Algebra },

year = { 1986 },

volume = { 39 },

pages = { 197-250 },

doi = { http://www.journals.elsevier.com/journal-of-pure-and-applied-algebra/ },

}