And there's the book by Vicente Rossi, Cosas de negros (which I haven't read), which touches upon the subject. I'd like to get my hands on a copy of the book to see what he has to say.
1958 reprint of the 1926 edition, with new foreword
I am somewhat hesitant about trying to disentangle the different strands of heritage in tango.
Things that are part of it (in loosely descending order of confidence)
-central european influence in that it is a partner dance
-African influence in that the tango is to some extent a response and adaptation of a (now lost?) traditon of afro-argentine dances (though there is still urugayan candombe)
-italian influences (singing style)
-central european/jewish influences ("singing" violins, the bandoneon/accordion was introduced by jewish musicians)
-arab influences (potentially the habanera rhythm through el andaluz)
and probably much more. There is not a lot of scholarly work that i could find, and the art history of love is very much a scholarly work of an art historian specializing in the afro-atlantic world applied, i.e. it does not attempt to describe the tango, it attempts to describe the african influence on the tango. When it comes up in discussions it seems to me that it is often read like a survey text about tango , which it isn't (and which i am pretty sure the author would agree with that). This is similar to how the slew of scholarly works that come from a feminist perspective attempt to trace the function of gender, sex, and their perceptions in tango. And how a hypothetical marxist reading of tango would all be about poverty, rich people slumming, the assimilation of low culture into high society, and so on.