Where are the law id-s?

Hello,
I have downloaded the Data Dumps from here https://static.openlegaldata.io/dumps/de/ and there is a refs.csv file, where the mapping between case and cited law is given. For the cases there are the id-s given in the cases.json file, but for laws in laws.json this is not the case. Is there any way to acess the relation between the laws and the respective id-s?