Whether Shelichutaaihu Ka'Avdinan applies to Gezeilot veChabbalot. Ketzot Hachoshen 1:3
Sources:
Mechaber and Ramah ChM. 1:3;
Rambam Sanhedrin 5:13;
Tosfot Sanhedrin 3a and B"K 84b
Nemukei Yosief B"K 84b
B"K 4b (See Rashi D"H Ganav)
Kessef Mishnah Sanhedrin 5:13
Semah 1:14
Shach 1:9
Vilna Gaon ChM 1:17-19