Modeling reversible reaction with 2 of the same reactants

[toelleri]

Need to verify that it correctly models:

A + A <-> B

Currently:

dA/dt = - ka * A * A + 2* kd * B
dB/dt = + ka * A * A - kd * B

Should be:

dA/dt = - 2ka * A * A + 2 kd * B
dB/dt = + ka * A * A - kd * B

This came up while modeling Fbn1 + Fbn1 <-> (Fbn1)_2 (Formation of Fbn1 dimer)