@article{ZNSL_2003_304_a1,
     author = {A. P. Beltiukov},
     title = {Weak constructive second order arithmetic with extracting polynomial time computable algorithms},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {7--12},
     publisher = {mathdoc},
     volume = {304},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2003_304_a1/}
}