Zusammenfassung: Akamine's (1986) BASIC program by Marquardt's method was rewritten for Richards model and its expanded model by the periodic function. For 0.9 similar to 1.1 the “LOG” function is corrected by Taylor series. Data estimated to be negative are cut off. AIC judges the effect of adding n to the parameters. Richards model is not so important in practice but it is important theoretically.