@article{TAM_1980_6_1_a3,
     author = {K. Firoozbakhsn and G. Ahmadi},
     title = {First strain gradient theory of granular materials},
     journal = {Theoretical and applied mechanics},
     pages = {50 },
     publisher = {mathdoc},
     volume = {6},
     number = {1},
     year = {1980},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAM_1980_6_1_a3/}
}