What kind of path can be specified in import statements?

The documentation only mentions `'path/to/soy/file/foo.soy'` about what kind of path should be specified in import statements.
Therefore, I have tried several patterns and expect that paths to soy file specified in import statements must match the format specified in the `--srcs` option.
However, this way is unstable because it depends on the working directory of executing compilation.
Please let me know if there is a better way for it.