The word 'condenser' consists of a nucleus 'dense' and two nonnuclei 'con-' and '-er'. The manner of dividing 'condenser' into immediate constituents may be complicated by the fact that the apparent partials 'condense' and 'denser' both make sense, but we immediately recognize that the form 'denser' contains quite a different morpheme, namely, the homophonous comparative '-er'. [...] The meaning is, of course, a very important guide, but it is not the only one and in some instances it is not too reliable. What does count is the substitutability. A verbe such 'condense' may be substituted for by a verb of a single morpheme, e.g. 'dance', and since 'dancer' consists of only two morphemes, there is not difficulty in deciding upon sets of immediate constituents
- Nida (1949), a pag.89

Divisions are made on the basis of the substitutability of larger units by smaller units belonging to the same or a different external distribution class.
- Nida (1949), a pag.91