17 CFR § 232.303 - Incorporation by reference.
(a) The following documents shall not be incorporated by reference into an electronic filing:
(1) Any document filed in paper in violation of mandated electronic filing requirements;
(2) Any document filed in paper pursuant to a hardship exemption for which a required confirming electronic copy has not been submitted.
(3) For a registered investment company or a business development company, documents that have not been filed in electronic format, unless the document has been filed in paper under a hardship exemption (§ 232.201 or 232.202 of this chapter) and any required confirming copy has been submitted.
(b) If a filer incorporates by reference into an electronic filing any portion of an annual or quarterly report to security holders, it must also file the portion of the annual or quarterly report to security holders in electronic format as an exhibit to the filing, as required by Regulation S–K Item 601(b)(13) (§ 229.601(b)(13) of this chapter). If a foreign private issuer incorporates by reference into an electronic filing any portion of an annual or other report to security holders, or of a Form 6–K report (§ 249.306 of this chapter) filed or submitted in paper, it also must file the incorporated portion in electronic format as an exhibit to the filing. The requirements of this paragraph do not apply to incorporation by reference by an investment company from an annual or quarterly report to security holders.