In the Texas matrimonial property system there are two kinds of property: separate property (solely owned by a spouse) and community property (owned in common in equal shares by both spouses). Typically, all property acquired during marriage by either spouse is presumed to be community property, and a spouse who asserts that particular property is separate property must prove its sole ownership. The principle of community property is derived from the law of Castile and ultimately from Visigothic custom. The other states that use this system are California, Louisiana, New Mexico, Arizona, Idaho, Nevada, Washington, and Wisconsin. During marriage all the earnings of both spouses and the revenues from the separate property acquired during marriage are community property. Between spouses, community property may become separate property by a gift or sale for a separate property consideration, or since 1980 by a partition or exchange entered into either before or during marriage. Separate property may be converted into community property by sale for a community property consideration. Otherwise, as long as its identity can be traced, separate property retains its character, but if separate property is commingled with community property so that it cannot be traced, the whole commingled mass is deemed common. Since 1987 spouses have been able to agree in writing that all or any part of their community property will belong to the survivor of them. Prior to 1913, and in large measure from 1929 to 1968, management of community property was vested in the husband. Since 1967 management of community property is clearly divided between the spouses according to its source. Each spouse has control of his or her earnings, the profits of separate property, and recoveries from personal injury for loss of earning power, but if that common property over which one spouse has sole management power is mixed or combined with that which is subject to the sole control of the other spouse, the resulting mixture is subject to joint control of the spouses. Spouses may, however, agree to manage their community property as they may choose. See also SEPARATE PROPERTY LAW.