Can you guys help me ID this one?

I assume it's from this 1970 edition:
http://www.ebay.com/itm/Encyclopedia-Britannica-full-set-of-24-Volumes-1...

I'm also doing a research on the most common Encyclopedia Britannica spine types.

Best,
Henrique Nardi

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A spine is the integral part of the common s structure in Latin types and fonts. Spines range in form from a simple diagonal line to s-shaped (including part of the upper and lower bowls), with and without stressing. The spine of some letter types such as constructivist and geometric consists of two right-angled joints joined by a horizontal crossbar. The term is borrowed from anatomical nomenclature.