Before revision: We introduce and study three classes of over-the-counter markets specified by systems of Ordinary Differential Equations (ODE's), in the spirit of Duffie-G\^{a rleanu-Pedersen , Over-the-Counter markets, Econometrica, 73 (2005) .
After revision: We introduce and study three classes of over-the-counter markets specified by systems of Ordinary Differential Equations (ODE's), in the spirit of Duffie-G\^{a rleanu-Pedersen 6 .