I posted the wrong (PL/I) link above, my bad! I checked again. It seems indeed like Fortran 70 was a spec that wasn't in use until fortran 77 in 1978. Thanks

I posted the wrong (PL/I) link above, my bad! I checked again. It seems indeed like Fortran 70 was a spec that wasn't in use until fortran 77 in 1978. Thanks again @vajrabum, I've update the article with your example!