@article{TAM_1982_8_1_a1,
     author = {Teodor Atanackovi\'c and Branislav Ba\v{c}li\'c},
     title = {An extremal variational principle for a class of boundary value problems},
     journal = {Theoretical and applied mechanics},
     pages = {13 },
     publisher = {mathdoc},
     volume = {8},
     number = {1},
     year = {1982},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAM_1982_8_1_a1/}
}