This has gone under several names in the literature, formule directrix (Euler), directrix, 1-permutation, and diagonal amongst others. (Dénes & Keedwell 1974, p. 29) Dénes, J.; Keedwell, A. D. (1974), Latin squares and their applications, New York-London: Academic Press, p. 547, ISBN0-12-209350-X, MR0351850
Bose, R. C.; Shrikhande, S. S.; Parker, E. T. (1960), "Further results on the construction of mutually orthogonal Latin squares and the falsity of Euler's conjecture", Canadian Journal of Mathematics, 12: 189–203, doi:10.4153/CJM-1960-016-5, MR0122729
Bose, R. C.; Shrikhande, S. S. (1959), "On the falsity of Euler's conjecture about the non-existence of two orthogonal Latin squares of order 4t + 2", Proceedings of the National Academy of Sciences USA, 45 (5): 734–737, Bibcode:1959PNAS...45..734B, doi:10.1073/pnas.45.5.734, PMC222625, PMID16590435
Bose, R. C.; Shrikhande, S. S.; Parker, E. T. (1960), "Further results on the construction of mutually orthogonal Latin squares and the falsity of Euler's conjecture", Canadian Journal of Mathematics, 12: 189–203, doi:10.4153/CJM-1960-016-5, MR0122729
Bruck, R.H.; Ryser, H.J. (1949), "The nonexistence of certain finite projective planes", Canadian Journal of Mathematics, 1: 88–93, doi:10.4153/cjm-1949-009-2, S2CID123440808
Bose, R. C.; Shrikhande, S. S. (1959), "On the falsity of Euler's conjecture about the non-existence of two orthogonal Latin squares of order 4t + 2", Proceedings of the National Academy of Sciences USA, 45 (5): 734–737, Bibcode:1959PNAS...45..734B, doi:10.1073/pnas.45.5.734, PMC222625, PMID16590435
Bose, R. C.; Shrikhande, S. S. (1959), "On the falsity of Euler's conjecture about the non-existence of two orthogonal Latin squares of order 4t + 2", Proceedings of the National Academy of Sciences USA, 45 (5): 734–737, Bibcode:1959PNAS...45..734B, doi:10.1073/pnas.45.5.734, PMC222625, PMID16590435
Bose, R. C.; Shrikhande, S. S. (1959), "On the falsity of Euler's conjecture about the non-existence of two orthogonal Latin squares of order 4t + 2", Proceedings of the National Academy of Sciences USA, 45 (5): 734–737, Bibcode:1959PNAS...45..734B, doi:10.1073/pnas.45.5.734, PMC222625, PMID16590435
Bruck, R.H.; Ryser, H.J. (1949), "The nonexistence of certain finite projective planes", Canadian Journal of Mathematics, 1: 88–93, doi:10.4153/cjm-1949-009-2, S2CID123440808