D. L. Clarke (1974)

Here's an old article in the Dutch publication "Paleaeohistoria" by D.L. Clarke concerning the various classifications of Beaker pottery in Britain.

In fact, the entire 12th edition is available with many highly referenced works by J.D. van der Waals, Humphrey Case and many others.

So why does this work matter?  As Sheridan points out the good, bad, ugly paper several posts ago,  David Clarke reordered the scheme of British beakers and associated many of them with traditions originating in continental Beaker groups of the Lower Rhine, in particular.

While some of the material is outdated, many of his observations are relevant for questions regarding who settled where.  You'll notice in the graphic a tendency of the long-neck style beakers to take a shape similar to some SGC pots:

"The tendency for increasingly tall and slender vessel shapes begins to appear in both of the earliest beaker groups, presumably reflecting the influence of the Protruding-Foot beakers of the Rhineland.  This feature is particularly noticeable amongst some of the Maritime beakers and becomes a constant feature in some of the following beaker groups from the Rhine-land."

Here's the link for this paper [here]

A Tentative Reclassification of British Beaker Pottery in the Light of Recent Research (Fig. I)

D.L. Clarke

Abstract

(p. 179)
The history of the analysis and classification of British Beakers between I870-I960 is too well known to need any lengthy restatement here. This complex 'tradition' has been summarised and restated in a more modern guise by Professor Piggott in his recent paper (I963). All that I wish to do at this stage is to emphasise four salient features underlying the current classification of British Beaker material.