Tiberius RIC 30 Style Groups

[Lucas H]

I have a denarius of Tiberius I believe to be RIC I 30.  Tiberius. 14-37 A.D. AR Denarius. Lugdunum (Lyon) Mint. 3.78 g., 19 mm. Obv: TI CAESAR DIVI AVG F AVGVSTVS, laureate head right. Rev: PONTIF MAXIM, Livia as Pax, seated right, holding scepter and olive branch. Feet on footstool. Ornate chair legs. One line below throne. RIC I 30, RSC 16a.

It is in my gallery here:

https://www.forumancientcoins.com/gallery/displayimage.php?pos=-66231

I've asked this before, but never got an answer, so I though I'd try again.  I can see the differences between the ornamental or plain chair legs, and RIC I 26, and RIC I 30, but I see references to style groups in listings for these coins.  A coin I purchased was advertised as "Group 4."  I assume the source is an article or publication.  Can someone please point me to it?  Where can I find these style groups?

[Lucas H]

No one can help point me to where the style groups for Tiberius denarii come from?

[bpmurphy]

The style groups come from:

Giard, Jean-Baptiste. Le Monnayage de L'Atelier de Lyon. Des Origenes au regne de Caligula (43 avant J.C - 41 Apres J.x.).

Barry Murphy

[Lucas H]

Thank you Mr. Murphey.  I have a few more questions now that I know what it is:

1.  I'm assuming it is not in an English language publication?
2.  Is it difficult/expensive to obtain?
3.  It is helpful?  

Any additional input is greatly appreciated.

[curtislclay]

It's in French, but most of the book is catalogue and plates, not text.

It's a fairly recent publication, so should be obtainable. Maybe it's even still in print.

It is somewhat useful, but falls far short of being the definitive catalogue and commentary on the coinage in question.