.Get_lambda             Get the lambda used to build a model
.Get_percent_predicted
                        Get % of expected value
.Get_reference_model    Get reference models
.Get_reference_percentile
                        Get percentile for a given combination of model
                        and measurement
.Get_reference_value    Get reference for a given combination of model
                        and percentile/z-score
.Get_reference_z_score
                        Get z-score for a given combination of model
                        and measurement
bodycomp_reference      Get body composition reference values
percent_predicted       Get % of expected value
reference_percentiles   Get percentile(s) for a given combination of
                        model and measurement
reference_values        Get reference values for a given combination of
                        model and percentile/z-score
reference_z_scores      Get z-scores for a given combination of model
                        and measurement
