Recommended Readings:

(1) Social Network Analysis, Author: Christina Prell
(2) SAGE Handbook of Social Network Analysis, Authors: John Scott & Peter J. Carrington

Journal Articles:
(1) Aref, S., Dinh, L., Rezapour, R., & Diesner, J. (2020). Multilevel structural evaluation of signed directed social networks based on balance theory. Scientific reports, 10(1), 1-12.
Link (open access):
(2) Dinh, L., Rezapour, R., Jiang, L., & Diesner, J. (2020). Structural balance in signed digraphs: considering transitivity to measure balance in graphs constructed by using different link signing methods.
(3) Aref, S., Mason, A. J., & Wilson, M. C. (2018). Computing the line index of balance using integer programming optimisation. InĀ Optimization problems in graph theory (pp. 65-84). Springer, Cham.