Add PDF mirror of SNB intro presentation
Reference implementations of the LDBC Social Network Benchmark's Interactive workload ([paper](https://homepages.cwi.nl/~boncz/snb-challenge/snb-sigmod.pdf), [specification on GitHub pages](https://ldbcouncil.org/ldbc_snb_docs/), [specification on arXiv](https://arxiv.org/pdf/2001.02299.pdf)).
-To get started with the LDBC SNB benchmarks, check out our introductory presentation: [The LDBC Social Network Benchmark](https://docs.google.com/presentation/d/1p-nuHarSOKCldZ9iEz__6_V3sJ5kbGWlzZHusudW_Cc/).
+To get started with the LDBC SNB benchmarks, check out our introductory presentation: [The LDBC Social Network Benchmark](https://docs.google.com/presentation/d/1p-nuHarSOKCldZ9iEz__6_V3sJ5kbGWlzZHusudW_Cc/) ([PDF](https://ldbcouncil.org/docs/presentations/ldbc-snb-2021-12.pdf)).
## Notes
