Original reference for Adams Riemann-Roch theorem 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.. 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 is for Grothendieck-Riemann-Roch.
 A: This seems both interesting and hard to pinpoint. Köck (1991; 1998, 4.6b) credits Fulton-Lang (1985) and Soulé (1985, cf. Thm 7), but your suggestion that the theorem must have been “known” earlier is also well-supported. For one thing, Rössler (1999, §1) finds it in Manin (1969, Thm 16.6). For another, Dyer (1962) (cited by Eckmann at ICM (1963), Adams (1965, (iii) p. 152), Fuchs (1973, pp. 349–350), and reprinted in Adams (1972)) starts:

This lecture is principally an exposition of a folk theorem of
  a Riemann-Roch type for general cohomology theories known to
  Adams, Atiyah, Hirzebruch... .

While these authors don’t spell out how this “folk” theorem includes yours, Panin (2004, §0.1; 2004, p. 823) says at least that his Theorem 2.5.3 “inspired by a Riemann-Roch theorem from [Dy]”, does. See also Smirnov (2006, 2.5.3).
So my impression is that specialists understood the Adams Riemann-Roch theorem as an instance of the more general Dyer-Riemann-Roch theorem, long before any of them bothered to name it.
