Fits simultaneous regression models to compare two sources
(reference and test) and estimates relative bioefficiency. Includes
simultaneous exponential model with common asymptote (model = 1),
slope-ratio model (model = 2), quadratic model (model = 3),
linear-response plateau model (model = 4), and Michaelis-Menten
model (model = 5). Output style follows the 'easyreg' package.
Methods are based on Finney (1978, ISBN:0-85264-252-0),
Mercer et al. (1978)