Source code: http://rickadams.org/adventure/e_downloads.html
Explanation: http://www.digitalhumanities.org/dhq/vol/001/2/000009/000009.html#section02 (not sure this matches to the source code link)
Play: https://www.amc.com/shows/halt-and-catch-fire/exclusives/colossal-cave-adventure
http://www.math-cs.gordon.edu/courses/cs323/FORTRAN/fortran.html
https://en.wikibooks.org/wiki/Fortran_77_Tutorial
http://www.icl.utk.edu/~mgates3/docs/fortran.html
gfortran compiler https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html
IBM Fortran IV http://bitsavers.trailing-edge.com/pdf/ibm/1130/lang/GC26-3715-8_1130_1800_Basic_FORTRAN_IV_Language_Jan73.pdf