"...An important practical extension to FORTRAN 77 was the release of MIL-STD-1753 in 1978. This specification, developed by the U.S. Department of Defense, sta

"...An important practical extension to FORTRAN 77 was the release of MIL-STD-1753 in 1978. This specification, developed by the U.S. Department of Defense, standardized a number of features implemented by most FORTRAN 77 compilers but not included in the ANSI FORTRAN 77 standard. These features would eventually be incorporated into the Fortran 90 standard. - DO WHILE and END DO statements - INCLUDE statement" - IMPLICIT NONE variant of the IMPLICIT statement - Bit manipulation intrinsic functions,..." [1] [1]: https://fortranwiki.org/fortran/show/FORTRAN+77 https://fortranwiki.org/fortran/show/FORTRAN+77