I earned a PhD in math from U of Maryland in 1965. In 1973 I translated all 4 volumes of Klein-Fricke Elliptic Modular Functions(vols 1 and 2) and Fricle-Klein Automorphic Functions(vols 3 and 4) from German to English, 2800 pages in all. So far no publisher has been willing to publish it. In 1993 I published Combinatorial Extension Cohomology in Advances in Mathematics, which was accepted by Rota in 30 days and published a year later. This paper rediscovered Lyndon's unpublished PhD thesis, and added the complementary half which he didn't do. The paper fully expresses the cohomology of a group extension in terms of the cohomology of the quotient of a group by a normal subgroup and the cohomology of the normal subgroup. A spectral sequence only gives a series of quotients and not how the quotients fit together.
I am now working on unrolling Gosper's and Hurwitz' recursions for expressing the continued fraction of a multiple of a fraction in terms of the continued fraction of this fraction globally, not relying on any recursion. As far as I know, this is new even for 2. I have finished 2 and 3 and am working on 4.