Better reference to scientific citation data in Problem 8M9

[opherdonchin]

Thank you for an excellent book.

Description

I assigned problem 8M9 to some students and they had difficulty finding the appropriate dataset of scientific citations referenced in the problem. I looked at the files in exercises\data in the GitHub and it looks to me like the correct file is sc.csv. However, it would be best if this was explicit in the text. It would be nice to also have references for the data files so that students could now where the data they are working on came from.

Reference

https://bayesiancomputationbook.com/markdown/chp_08.html

Author Section

Do not close until

• Added to Errata
• Fixed in Open Access
• Fixed in latex source