Mirror: description or interpretation in the form of 'implicit quotation'

I don't know whether there is such a term or pattern in English grammar or style as 'implicit quotations', but I find very often something like that in English writings. I mean by it that:

• there is no quotation marks; 
• there is no explicit indications of speakers other than the writer herself, like 'according to' or 'someone says'; 
• but the 'true' or 'original' speaker is surely not the writer herself; the latter often serves as an interpreter, reader or someone like reteller of the former.

This post is just an exercise to get familiar with such an element of writing.

Let's take up a sample paragraph:

So it is not surprising that the theories, although expressed in the elegant algebra beloved of modern economists, were simple. Solow's model of growth remained the basic workhorse theory until the 1980s. It said that the economy's growth of its total output depended on the growth in the inputs needed─land or materials, labor and capital─and an unexplained remainder or residual labeled "technical progress." When applied to actual GDP data, the results were mildly embarrassing for the theory, because studies revealed that the great majority of postwar GDP growth was "explained" by the "technical progress," that is, by the one part of the theory that had no economic explanation. Technical progress was treated in this growth model as manna from heaven.

And the part of sentences which immediately follow, it seems, can be viewed as an 'implicit quotation.' 

Business investment created new capital to use in production. Labor grew by an increasing working-age population and, as the growth models became more refined, the increasing level of education and skill in the workforce. Both contributed to growth, but "technology" explained more.