Morphological sequence classes are of two principal types: (1) those which have at least one nonrooot immediate constituent and (2) those which have only root-containing immediate constituents. The second type of sequence class has syntactic parallels.
- Nida (1949), a pag.108

Morphological sequence classes of the first type may include the following: 1. Stem plus affix [...]. 2. Stem plus replacive [...]. 3. Stem plus subtractive [...]. 4. Stem plus stem [...]. 5. Stem plus inflectional formative [...].
- Nida (1949), a pag.108-109

Sequence classes of the second type are parallel to or in contrast with the syntactic structure. In English they may be illustrated by the following: Syntactic sequence classes in morphological constructions: 1. Adjective plus noun, e.g. 'blackbird', 'greenhouse', and 'Redcoat'. 2. Noun plus noun, e.g. 'goldfish', 'beefsteak', and 'seacoast'. [...] Nonsyntactic sequence classes in morphological constructions: 1. Adverb plus verb, e.g. 'backfire', 'upset', and 'outcry'. 2. Verb plus noun, e.g. 'playground', 'gocart', and 'outcry'. [...]
- Nida (1949), a pag.109