Gene Symbol Mappings

How can/should I lookup *all* the known mappings between different representations of symbol names?

For example, B6 maps to C57BL/6J and D2 maps to DBA/2J.

I'll need that mapping information for every strain, symbol etc... that has an alias in order to make the conversions.

Ideally, I can have those mappings in some machine-readable format like csv, json, etc...