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Sustained is an alternative term. Since suspended is more common (and more correct), we switched to the term suspended years ago, but some mentions have survived. I call them sus chords, so haven't thought about it in a long time.
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http://en.wikiversity.org/wiki/Introduction_to_Chords

Suspended(Sustained) Chord
The suspended chord, also called sustained chord, is symbolized with "sus" or "sus4" (e.g. Bbsus | Bbsus4). Another version of this chord is symbolized with "sus2" (e.g. Bbsus2). The 4 type combines the first, fourth, and fifth note, while the 2 type is first, second, and fifth.
Bb - Eb - F (Sus4)
Bb - C - F (Sus2)

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Btw, this issue was already corrected, so only applies to older versions of BiaB documentation.

Have Fun!
Peter Gannon
PG Music Inc.