That concept of Reference isn't actually a part of the core JSON spec (i.e. ECMA-404), but an add-on that can be expressed in JSON and interpreted by a parser that can do JSON References.
The TOML spec is like ECMA-404, in that it's all about the core language. References could be done similarly to how they're done in JSON, like so:
[external]
"$ref" = "http://some/where"
A TOML references spec, if one were made, wouldn't belong to the core TOML spec, though. It would be a complementary specification.
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That concept of Reference isn't actually a part of the core JSON spec (i.e. ECMA-404), but an add-on that can be expressed in JSON and interpreted by a parser that can do JSON References.
The TOML spec is like ECMA-404, in that it's all about the core language. References could be done similarly to how they're done in JSON, like so:
A TOML references spec, if one were made, wouldn't belong to the core TOML spec, though. It would be a complementary specification.