Sequence classes [...] are any sequence of forms constituting a construction. For example, the combination 'good man' belongs to an adjective-noun sequence class, to which such phrases as 'red house', 'bad chimney', and 'fischy story' also belong. This sequence class differs from such sequence classes as adverb-adjective 'very good', noun-verb (or subject-predicate) 'John ran', and preposition-object 'for me'.
- Nida (1949), Pag. 103

Sequence classes consist of a sequences of morphemes in which the corresponding immediate constituents belong to structurally parallel external distribution classes. Structural parallelism is defined as occurrence whith the same class of costituents and in the same order.
- Nida (1949), Pag. 108

There are two primary types of distribution in single sequence classes: (1) those in which there are determiner and determined immediate constituents and (2) those in which there is no such determiner-determined relationship. The first type includes structural series in which the determiner is a single morpheme or a set of supplementary or complementary morphemes. The members of the determiner immediate constituent are strictly limited in number, and the members of the determined immediate constituent are equal in number to the number of forms in the structural series. The second type of distributional arrangements involves compounds, in which there are approximately the same number of different memebrs in each immediate-constituent series.
- Nida (1949), Pag. 112

Sequence classes are a special type of distribution class.
- Nida (1949), Pag. 107