Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1979_26_4_a1, author = {Yu. G. Penzin}, title = {Twins problem in formal arithmetic}, journal = {Matemati\v{c}eskie zametki}, pages = {505--511}, publisher = {mathdoc}, volume = {26}, number = {4}, year = {1979}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1979_26_4_a1/} }
Yu. G. Penzin. Twins problem in formal arithmetic. Matematičeskie zametki, Tome 26 (1979) no. 4, pp. 505-511. http://geodesic.mathdoc.fr/item/MZM_1979_26_4_a1/