@article{PIM_1975_N_S_19_33_a19,
     author = {Slavi\v{s}a B. Pre\v{s}i\'c},
     title = {Equational {Reformulation} {Of} {Formal} {Theories}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {131 },
     publisher = {mathdoc},
     volume = {_N_S_19},
     number = {33},
     year = {1975},
     url = {http://geodesic.mathdoc.fr/item/PIM_1975_N_S_19_33_a19/}
}