Section 8. The forms set forth in the appendix to this chapter may be used and shall be sufficient for their respective purposes. They shall be known as ”Statutory Forms” and may be referred to as such. They may be altered as circumstances require, and the authorization of such forms shall not prevent the use of other forms. Wherever the phrase ”incorporation by reference” is used in the following sections, the method of incorporation as indicated in said forms shall be sufficient, but shall not preclude other methods.