This defines a regular expression that a GRid must conform to. GRids that are non conformant will cause the entire file to be rejected. GRids are to be formatted with no spaces or hiphens within the GRid code. This defines a regular expression that a ISRC must conform to. ISRCs that are non conformant will cause the entire file to be rejected. ISRCs are to be formatted with no spaces or hiphens within the ISRC code.