Let $f\colon Y\to X$ be a proper morphism between smooth quasiprojective $k$-algebraic varieties. Denote by $\psi^j$ the $j$-th Adams operation on the Grothendieck group of vector bundles and $\theta^j(T_f)$ the $j$-th cannibalistic class of the relative tangent bundle $T_f$. The Adams Riemann-Roch theorem states that for any $j$ the diagram $\require{AMScd}$ $$ \begin{CD} K_0(Y)@>f_*>>K_0(X)\\ @V\theta^j(T_f)\cdot \psi^jVV@VV\psi^jV\\ K_0(Y)\otimes\mathbb{Z}[\tfrac{1}{j}]@>f_*>>K_0(X) \otimes \mathbb{Z}[\tfrac{1}{j}] \end{CD} $$ commutes. The oldest reference I know is Theorem 7.6 of Chapter V in [W. Fulton; S. Lang: Riemann-Roch algebra. Grundlehren der Mathematischen Wissenschaften , 277. Springer-Verlag, New York, 1985. x+203 pp.][1]. However, that reference is already very general (it does not even require schemes to be over a field) and 1985 is very "late" for such a Riemann-Roch type statement. Therefore my question: $ \phantom{aaaaaaaa}$**What is the original reference for the Adams Riemann-Roch theorem?** I am looking for something as [Borel-Serre's paper][2] is for Grothendieck-Riemann-Roch. [1]: https://link.springer.com/book/10.1007/978-1-4757-1858-4 [2]: http://www.numdam.org/item/BSMF_1958__86__97_0/