משנה על נזיר 7:2

Two are defiled through a corpse, one being defiled with seven days' defilement and one being defiled with a defilement lasting until the evening. Three are defiled through a corpse, two being defiled with seven days’ defilement and one with a defilement lasting until the evening. Four are defiled through a corpse, three being defiled with seven days’ defilement and one with a defilement lasting until the evening. What [is the case of] two? A person who touches a corpse is defiled with seven days’ defilement and a person who touches him is defiled with a defilement lasting until the evening.

What [is the case of] three? Vessels touching a corpse and [other] vessels [touching these] vessels are defiled with seven days’ defilement. The third: whether a person or vessels, is defiled with a defilement lasting until the evening.

What is the case of four? Vessels touching a corpse, a person [touching these] vessels, and [other] vessels [touching this] person, are defiled with seven days' defilement. The fourth, whether a person or vessels, is defiled with a defilement [lasting until the] evening. Rabbi Akiva said: I have a fifth, [if] a peg was fixed in a tent, the tent, the peg, a person touching the peg and vessels [touching] the person are defiled with seven days' defilement. The fifth, whether a person or vessels, is defiled with a defilement [lasting until the] evening. They said to him: the tent does not count.