"Reference" was the original term used in the languages derived from ALGOL for what is now called "pointer".

The distinction that exists in C++ between "reference" and "pointer" is something very recent. In the past the 2 terms were synonymous.

The term "pointer" was introduced by IBM PL/I in July 1966, where it replaced "reference".

PL/I has introduced many terms that have replaced previously used terms. For example:

reference => pointer

record => structure

process => task

and a few others that I do not remember right now.

"Pointer" and "structure" have become dominant after they have been taken by the C language from PL/I and then C has become extremely popular. Previously "reference" and "record" were more frequently used.

But the "references" in Euler seem to be close to references nowadays. There is no access to the address, no pointer arithmetic etc. such as in PL/I.