Προσθέτω και λίγες πληροφορίες από το Lexicography: A Dictionary of Basic Terminology:
SLIP
Slips are cards -pieces of paper or cardboard of a standard size- on which citations, i.e. verbal contexts of lexical items can be copied. Once copied on a slip, a particular word form of a given lexical item with its context becomes a sample taken from a primary source, i.e. a piece of lexicographic material. […]
COLLECT
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In the pre-computer era the major way of collecting lexicographic data was to accumulate a set of systematically-organized citation slips. The advantage of slips over, for instance, book listings, was as follows. Each slip could be moved elsewhere; thus slips could be rearranged at any time, when required. Instead of an alphabetically-ordered collection of slips, i.e. citation file, the same slips could be organized differently; for instance, according to the frequency of usage of the lexical items, their morphological composition, semantic affinity, etymology, syntactic properties, valence, etc.