Celebratio Mathematica

L. A. Coburn, R. G. Douglas, D. G. Schaef­fer, and I. M. Sing­er: “\( C^* \)-al­geb­ras of op­er­at­ors on a half-space, II: In­dex the­ory,” Inst. Hautes Études Sci. Publ. Math. 40 (1971), pp. 69–​79. MR 358418 Zbl 0241.​47027 article

L. A. Coburn, R. G. Douglas, and I. M. Sing­er: “An in­dex the­or­em for Wien­er–Hopf op­er­at­ors on the dis­crete quarter-plane,” J. Diff. Geom. 6 : 4 (1972), pp. 587–​593. This is­sue is ded­ic­ated to S. S. Chern and D. C. Spen­cer on their six­tieth birth­days. MR 321142 Zbl 0252.​47026 article