Central Tehran Branch. IAUJournal of Linear and Topological Algebra (JLTA)2252-0201060120170601Unique common coupled fixed point theorem for four maps in $S_b$-metric spaces2943530217ENK. P. R. RaoDepartment of Mathematics, Acharya Nagarjuna University, Nagarjuna Nagar,
Guntur-522 510, Andhra Pradesh, IndiaG. V. N. KishoreDepartment of Mathematics, K L University, Vaddeswaram, Guntur-522 502,
Andhra Pradesh, IndiaSk. SadikDepartment of Mathematics, Sir C R R College of Engineering, Eluru,
West Godavari-534 007, Andhra Pradesh, India20170202http://jlta.iauctb.ac.ir/article_530217_56934be0fc2de05532e4acfcd9699735.pdf