Definition of agreements or contrac

Definition of agreements or contracts set forth in Article 1313 of the Civil Code. Article 1313 of the Civil Code is “someone or more make agreement by him/herselves or themselves.."
According to the new theory by Van Dunne, which is defined by the agreement, is "a legal relation between two people or more based on an agreement to give a legal consequences."
According to Salim HS, SH, MH, agreement or contract is a legal relation between the subjects with other subjects in the field of wealth, where the one subject get the achiement and the other subject is obliged must doing achieved as according to agreed.
According Subekti, an agreement is instance when the people make a promise to other people or themselves make a promise to do something. From this, relation between two people or more is called engagement. In fromed, the agreement is a series of words that contain promises that is spoken or written.
And then the relation between the engagement and agreement is that the agreement to make the engagement. Agreement is a source of engagement, beside the other sources. Other sources include laws. So, there is an engagement is born of the agreement and there is an engagement that was born of law.
By definity the many agreements that have been described above, there are three elements that can be deduced, it is:
1. the person has claim, or in business terms usually called creditors
2. the person has required, in business terms usually called debtor
3. There is something that is required, it is achievement.