1 The regenerative capacity of the notochordal cell: tissue constructs generated in vitro under hypoxic conditions 3 P6 }& ] L' K4 Z8 Ahttp://www.ncbi.nlm.nih.gov/pubmed/19558283 & A: @; F3 l e2 n2 The functional significance of cell clusters in the notochordal nucleus pulposus: survival and signaling in the canine intervertebral disc.( ~- i- `+ \2 F1 i http://www.ncbi.nlm.nih.gov/pubmed/15131437 7 f( U# d0 t" `4 L- u) A# q: E5 I: q& ~; f9 a, c