Geodesic
Automorphisms of a strongly regular graph with parameters $(1197,156,15,21)$
Vladikavkazskij matematičeskij žurnal, Tome 17 (2015) no. 2, pp. 5-11 
V. V. Bitkina; A. K. Gutnova; A. A. Makhnev. Automorphisms of a strongly regular graph with parameters $(1197,156,15,21)$. Vladikavkazskij matematičeskij žurnal, Tome 17 (2015) no. 2, pp. 5-11. http://geodesic.mathdoc.fr/item/VMJ_2015_17_2_a0/
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     author = {V. V. Bitkina and A. K. Gutnova and A. A. Makhnev},
     title = {Automorphisms of a~strongly regular graph with parameters $(1197,156,15,21)$},
     journal = {Vladikavkazskij matemati\v{c}eskij \v{z}urnal},
     pages = {5--11},
     year = {2015},
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     url = {http://geodesic.mathdoc.fr/item/VMJ_2015_17_2_a0/}
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Voir la notice de l'article provenant de la source Math-Net.Ru

Let a $3$-$(V,K,\Lambda)$ scheme $\mathscr E=(X,\mathscr B)$ is an extension of a symmetric $2$-scheme. Then either $\mathscr E$ is Hadamard $3$-$(4\Lambda+4,2\Lambda+2,\Lambda)$ scheme, or $V=(\Lambda+1)(\Lambda^2+5\Lambda+5)$ and $K=(\Lambda+1)(\Lambda+2)$, or $V=496$, $K=40$ and $\Lambda=3$. The complementary graph of a block graph of $3$-$(496,40,3)$ scheme is strongly regular with parameters $(6138,1197,156,252)$ and the neighborhoods of its vertices are strongly regular with parameters $(1197,156,15,21)$. In this paper automorphisms of strongly regular graph with parameters $(1197,156,15,21)$ are studied. We yet introduce the structure of automorphism groups of abovementioned graph in vetrex symmetric case.

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