DLS (Metro 2033)

a good time of being hardworking, do not tell me that DLS last lgiht?I saw in Wikipedia 2 DLS which has never been heard or seen, the incentive was some article, but not found in the store, do not tell me where to buy?or any info on it?
http://ru.metro.wikia.com/wiki/Developer_Pack
http://ru.metro.wikia.com/wiki/Chronicles_Pack