Relative Bioefficiency via Simultaneous Regressions // 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) doi:10.1093/jn/108.8.1244, Robbins et al. (1979) doi:10.1093/jn/109.10.1710, Noll et al. (1984) doi:10.3382/ps.0632458, Gallant and Fuller (1973) doi:10.1080/01621459.1973.10481356, Littell et al. (1997) doi:10.2527/1997.75102672x, and Burnham and Anderson (2002, ISBN:978-0-387-95364-9).