Complex sentences consist of an independent clause plus one or more dependent clause(s). (Gibson, 1973, p. 77) They may also consist of a main clause and one or more of the following embedded clauses: relative clauses, subordinate clauses, and nominalized clauses. (Suttles, 2003, p. 94)
Gibson, J. A. (1973). Shuswap grammatical structure. [Doctoral dissertation, The University of Hawaii].
Suttles, W. (2004). Musqueum reference grammar. UBC Press. SFU Student Access.