Throughout this paper R denotes a commutative ring with identity and M denotes a unital
R-module. L(R) (L(M)) denotes the lattice of all ideals of R (submodules of M). For any two
submodules N and K of M, the ideal {a ∈ R | aK ⊆ N} will be denoted by (N : K). Thus
(O : M) is the annihilator of M. M is said to be a faithful module if (O : M) is the zero ideal
of R. M is said to be a multiplication module [4] if every submodule of M is of the form IM,
for some ideal I of R. According to [7], a submodule N of M is called meet-quasi-cyclic (or
meet principal in the sense of [1, 3]) if (B ∩ (K : N))N = BN ∩ K for all ideals B of R and
for all submodules K of M; N is called weak-join-quasi-cyclic if (BN) : N = (0 : N) + B for
all ideals B of R; N is called join-quasi-cyclic (or join principal in the sense of [1] and [3]) if
(K + BN) : N = (K : N) + B for all ideals B of R and for all submodules K of M. N is called
quasi-cyclic [7] (or principal in the sense of [1] and [3])if N is both meet-quasi-cyclic and
join-quasi-cyclic. Note that quasi-cyclic submodules have been studied in [1], [3] and [7].