I would recomend to start with checking in such journals as The Journal of Juristic Papyrology.

Best regards,

Lukasz

You might try this as a starting point: Alan Watson, The Evolution of Law: The Roman System of Contracts

http://digitalcommons.law.uga.edu/cgi/viewcontent.cgi?article=1491&context=fac_artchop

Another good starting point might be J A Crook's book, Law and Life of Rome, which does have some detailed discussions on Societas and related legal topics.  (See Index.) 

Mario Talamanca, La 'societas'. Corso di lezioni di diritto romano, Milano, CEDAM, 2012

Perhaps you should take a look in the works of Ernst Badian like Publicans and sinners

Arrangio-Ruiz, la società in diritto romano novene Napoli 1950

talamanca, s.v. Societaà (diritto romano) in enciclopedia del diritto 42 1990. 

Michael Wegner, Untersuchungen zu den lateinischen Begriffen socius und societas , Göttingen 1969.

If you are seeking just scholarly articles, I suggest you search JSTOR You will find, for example, works such as; Law and Finance "at the Origin" Ulrike Malmendier

Journal of Economic Literature, Vol. 47, No. 4 (DECEMBER 2009), pp. 1076-1108; Societas as Consensual Contrac David Daube The Cambridge Law Journal, Vol. 6, No. 3 (1938), pp. 381-403; 

Because there are so many, you may want to limit your searches to JRS.

There is a paper by Bonet (published in 1948 in Anuario de historia del derecho español) on the subject of " societas publicanorun"  that even if it is in spanish has an excellent list of sources that can be useful .

I send you the pdf file