Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 248
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 248, with English translation by Maimonides (Rambam).
לדון בדיני נחלות, שנאמר: "איש כי ימות, ובן אין לו" (במדבר כז,ח).
To render judgment [in questions] regarding inheritances as [Numbers 27:8] states: "If a person dies without having a son...."