134 Yevamot 2/4-6

(ד) אִסּוּר מִצְוָה, שְׁנִיּוֹת מִדִּבְרֵי סוֹפְרִים. אִסּוּר קְדֻשָּׁה, אַלְמָנָה לְכֹהֵן גָּדוֹל, גְּרוּשָׁה וַחֲלוּצָה לְכֹהֵן הֶדְיוֹט, מַמְזֶרֶת וּנְתִינָה לְיִשְׂרָאֵל, וּבַת יִשְׂרָאֵל לְנָתִין וּמַמְזֵר:

(ה) מִי שֶׁיֶּשׁ לוֹ אָח מִכָּל מָקוֹם, זוֹקֵק אֶת אֵשֶׁת אָחִיו לְיִבּוּם, וְאָחִיו לְכָל דָּבָר, חוּץ מִמִּי שֶׁיֶּשׁ לוֹ מִן הַשִּׁפְחָה וּמִן הַנָּכְרִית. מִי שֶׁיֶּשׁ לוֹ בֵּן מִכָּל מָקוֹם, פּוֹטֵר אֵשֶׁת אָבִיו מִן הַיִּבּוּם, וְחַיָּב עַל מַכָּתוֹ וְעַל קִלְלָתוֹ, וּבְנוֹ הוּא לְכָל דָּבָר, חוּץ מִמִּי שֶׁיֶּשׁ לוֹ מִן הַשִּׁפְחָה וּמִן הַנָּכְרִית:

(ו) מִי שֶׁקִּדֵּשׁ אַחַת מִשְּׁתֵּי אֲחָיוֹת וְאֵינוֹ יוֹדֵעַ אֵיזוֹ מֵהֶן קִדֵּשׁ, נוֹתֵן גֵּט לָזוֹ וְגֵט לָזוֹ. מֵת, וְלוֹ אָח אֶחָד, חוֹלֵץ לִשְׁתֵּיהֶן. הָיוּ לוֹ שְׁנַיִם, אֶחָד חוֹלֵץ וְאֶחָד מְיַבֵּם. קָדְמוּ וְכָנְסוּ, אֵין מוֹצִיאִין מִיָּדָם:

(4) A prohibition commandment [refers to] the secondary degrees [of forbidden unions] prohibited by rabbinic decree. A prohibition due to sanctity [refers to] a widow [marrying] a high priest, a divorced woman or a Chalutzah [a woman who performs Chalitzah, marrying] a common priest, a Mamzeret [the offspring of a severely prohibited union between a Jewish man and woman] or a Netinah [a member of a caste of Temple servants historically descended from the Gibeonites, marrying] a Jew, and the daughter of a Jew [marrying] a Mamzer or a Netin.

(5) [If] one has any kind of a brother [even a Mamzer] he [such a brother] binds his [dead] brother's wife to Yibum. And he is his brother with regard to all matters, except when one has [a brother] from a bondwoman, or from a gentile woman. [If] one has any kind of a son [even a Mamzer] he exempts his father's wife from Yibum; and he is liable for striking him [his father] or cursing him [his father]. And he is his son with regard to all matters, except when one has [a son] from a bondwoman, or from a gentile woman.

(6) [If] one betrothed one of two sisters, but does not know which of them he betrothed, he gives a bill of divorce to this one and a bill of divorce to that one. If he died and he had one brother, he [that brother] undergoes Chalitzah from both [women]. If he had two brothers, one undergoes Chalitzah [from one woman] and one performs Yibum [with the other woman]. [If] they went ahead and married [the sisters] they [the women] are not removed from them.