0) Thomas Graham
Graham's first paper on the Pd-H system was published in 1866 (see below).
In the literature (at least up to 2019), when referring to the discovery of Pd-H, an overwhelming amount of authors do only cite his first paper, yet Graham's work on this system was pursued after 1866 :
His 1st paper (1866) : https://doi.org/10.1098/rstl.1866.0018 see page 426.
His 2nd paper (1868) : https://doi.org/10.1098/rspl.1867.0090
His 3rd paper (1869) : https://doi.org/10.1098/rspl.1868.0030
His 4th paper (1869) : https://doi.org/10.1098/rspl.1868.0103
One can remark that this work was done at the end of Grahams's career (he passed away in 1869).
See below the section X.1).
The paper under the 1967 red book is an appreciation made by Ted B. Flanagan in 2008 about F.A. Lewis (deceased in 2007). This appreciation can be found here. This paper is interesting for various reasons, including : Ted reviewed the major Lewis' contributions on Pd-H and its alloys.
F.A. Lewis made a gigantic amount of contributions on the Pd-H(D) system and its alloys. Specific post(s) will be made later for that.
An almost identical material was presented by T.B. Flanagan in 1989 at the EPRI-NSF Workshop on anomalous effects in Deuterided metals, Wasington D.C., USA, published in the proceedings* and can be found here below in the black box. This version is worth exploring for various reasons, notably it includes an interesting dialogue between Flanagan and some attendees such as R.A. Oriani, J.O'M. Bockris, ...
Besides, it is a great pity that dialogues between the speaker and attendees (during questions session) do not appear in the proceedings anymore (as it was apparently the case in the past).
* : The book of proceedings can be found in the ResearchGate profile of T.B. Flanagan : here.
How to download this book :
- go to the LibGen website,
- and enter "engelhard industries",
- bingo !
X.2.a) References cited in "High pressure synthesis and thermodynamic stability of PdH(1+/-epsilon) up to 8 GPa"
X.2.a.5) Ref  is :
M. Tkacz and B. Baranowski,
Solubility of hydrogen in palladium hydride at high pressure of gaseous hydrogen,
Roczniki Chemii, Ann. Soc. Chim. Polonorum, 50 (1976) 2159-2166,
and is [X1160] in our own classification and can be downloaded in the blue box below.
X.2.a.6) Ref  is :
Pressure-composition studies on the palladium-gold-hydrogen system up to 10 kbar at 25°C,
Polish Journal of Chemistry, 55 (1981) 2137-2141,
and is [X826] in our own classification and can be downloaded in the blue box below.
A high resolution scan of [X826]'s Figure page 2138 can be downloaded here :
X.2.b) References cited in "First-principles study of the atomic volume of Hydrogen in Palladium"