# Bread for Sandwiches

### Description

Generic function for extracting an estimator for the bread of sandwiches.

### Usage

1 |

### Arguments

`x` |
a fitted model object. |

`...` |
arguments passed to methods. |

### Value

A matrix containing an estimator for the expectation of the negative
derivative of the estimating functions, usually the Hessian.
Typically, this should be an *k x k* matrix corresponding
to *k* parameters. The rows and columns should be named
as in `coef`

or `terms`

, respectively.

### References

Zeileis A (2006), Object-Oriented Computation of Sandwich Estimators.
*Journal of Statistical Software*, **16**(9), 1–16.
URL http://www.jstatsoft.org/v16/i09/.

### See Also

`lm`

, `glm`

### Examples

1 2 3 4 5 6 7 8 |

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