New Revised Standard Version
and that he appeared to Cephas, then to the twelve.

Contemporary English Version
Christ appeared to Peter, then to the twelve.

New American Bible
that he appeared to Cephas, then to the Twelve.

Douay-Rheims Bible
And that he was seen by Cephas, and after that by the eleven.

And that he was seen by Cephas, and after that by the eleven.

that.

Luke 24:34 Saying: The Lord is risen indeed and hath appeared to Simon.

*etc:

Cephas.

1 Corinthians 1:12 Now this I say, that every one of you saith: I indeed am of Paul; and I am of Apollo; and I of Cephas; and I of Christ.

1 Corinthians 3:22 For all things are yours, whether it be Paul or Apollo or Cephas, or the world, or life, or death, or things present, or things to come. For all are yours.

1 Corinthians 9:5 Have we not power to carry about a woman, a sister as well as the rest of the apostles and the brethren of the Lord and Cephas?

John 1:42 And he brought him to Jesus. And Jesus looking upon him, said: Thou art Simon the son of Jona. Thou shalt be called Cephas, which is interpreted Peter.

then.

Mark 16:14 At length he appeared to the eleven as they were at table: and he upbraided them with their incredulity and hardness of heart, because they did not believe them who had seen him after he was risen again.

Luke 24:36 Now, whilst they were speaking these things, Jesus stood in the midst of them and saith to them: Peace be to you. It is I: Fear not.

*etc:

John 20:19-26 Now when it was late the same day, the first of the week, and the doors were shut, where the disciples were gathered together, for fear of the Jews, Jesus came and stood in the midst and said to them: Peace be to you. . . .

Acts 1:2-14 Until the day on which, giving commandments by the Holy Ghost to the apostles whom he had chosen, he was taken up. . . .

Acts 10:41 Not to all the people, but to witnesses preordained by God, even to us, who did eat and drink with him, after he arose again from the dead.