This is the basic model described in eq. 1 of the article:
A model of phosphofructokinase and glycolytic oscillations in the pancreatic beta-cell.
Westermark PO and Lansner A. Biophys J. 2003 Jul;85(1):126-39. PMID:
12829470, doi:10.1016/S0006-3495(03)74460-9
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