مناسك حج - مكارم شيرازى، ناصر - الصفحة ١٨١ - Rulings of Wuquf in Arafat and Mash'ar
٥ -Sacrifice
Article ٢٨٧- The second obligatory act of Mena is sacrifice and camel is the best for this purpose and its middle is a cow and the least of that is a sheep and this is obligatory for only those who are performing Hajj al- Tamattu and it is not obligatory for the others.
Article ٢٨٨- It is obligatory precaution that a sacrifice to be only for one person even in the cases of necessity; and if some persons are capable of sacrifice only one animal, then it is precaution to perform fasting, which will be mentioned later, added to sacrifice; but it has no problem to sacrifice only one animal for a group of people in Mustahab sacrifices like the Eid of Qurban even they are seventy persons.
Article ٢٨٩- It is better to perform Zebh( ritual slaughter )in the day of the Eid but it is permitted to delay that until the thirteenth day.