Arnold Oberschelp. On Pairs and Tuples. Math. Log. Q., 37(2-4):55-56, 1991. [doi]
@article{Oberschelp91, title = {On Pairs and Tuples}, author = {Arnold Oberschelp}, year = {1991}, doi = {10.1002/malq.19910370207}, url = {http://dx.doi.org/10.1002/malq.19910370207}, researchr = {https://researchr.org/publication/Oberschelp91}, cites = {0}, citedby = {0}, journal = {Math. Log. Q.}, volume = {37}, number = {2-4}, pages = {55-56}, }