I have one other thought.

See if you can find a Fifth edition of the Piping Handbook by R.C. King and Sabin Crocker on the Internet used book sites. It must be a Fifth Edition as (I think) this was the last edition that included the article by John Brock, titled "Expansion and Flexibility". I am currently without a copy as I have had two of them "wander away" in the last 10 years.

Anyway, there is a wealth of understanding to be had if you read the Brock article and he even includes as an appendix the original final report of the ASA B31 "Flexibility Committee" circa 1955.

The latest (7th) edition of the Piping Handbook is a wonderful tool and it represents a "labor of love" from Mohinder L. Nayyar. I have copies of the last few of these. I would gladly buy a 7th edition to swap "even-up" with anybody who has a fifth edition in good condition. Anyway,this is not the Markl Papers but it is good stuff.

Regards, John