Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 223
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 223, with English translation by Maimonides (Rambam).
לעשות לסוטה כתורה, שנאמר: "ועשה לה הכוהן, את כל התורה הזאת" (במדבר ה,ל).
To carry out the [procedure] prescribed for a sotah, as [Numbers 5:30] states: "And the priests will carry out all these laws for her."