///<reference doesn't work with absolute paths

A file 0.ts references a file 1.ts in a windows directory called C:\Work. When referenced like this it works:

``` TS
///<reference path="1.ts"/>
```

But the following reference does not work:

``` TS
///<reference path="C:\Work\1.ts"/>
```

The error the compiler gives is
error TS6053: File 'C:/Work/C:/Work/1.ts' not found.
