and his family

What did Abu Bakr (saw) write to Anas (saw) about the Zakat that Allah had ordered the Prophet Muhammad (saw) to observe?
 Narrated Anas:                     Abu Bakr , wrote to me about the Zakat which Allah had ordered His Apostle to observe: Whoever had to pay Jahda (Jahda means a four-year-old she-camel) as Zakat from his herd of camels and he had not got one, and he had Hiqqa (three-year-old she-camel), that Hiqqa should be accepted from him along with two sheep if they were available or twenty Dirhams (one Durham equals about 1/4 Saudi Riyal) and whoever had to pay Hiqqa as Zakat and he had no Hiqqa but had a Jadha, the Jadha should be accepted from him, and the Zakat collector should repay him twenty Dirhams or two sheep; and whoever had to pay Hiqqa as Zakat and he had not got one, but had a Bint Labun (two-year-old she-camel), it should be accepted from him along with two sheep or twenty Dirhams; and whoever had to pay Bint Labun and had a Hiqqa, that Hiqqa should be accepted from him and the Zakat collector should repay him twenty Dirhams or two sheep; and whoever had to pay Bint Labun and he had not got one but had a Bint Makhad (one-year-old she camel), that Bint Makhad should be accepted from him along with twenty Dirhams or two sheep.