Analysis of information sources in references of the Wikipedia article "老挝" in Chinese language version.
lao larb.
Sang Sinxay entry
...Lord Sam Chon, the ruler of Müang Chot, came to attack Müang Tak....
khun : ruler of a fortified town and its surrounding villages, together called a mu'ang. In older sources the prefix ph'o ("father") is sometimes used as well.
Examples of the first are söaṅ, the name of Ram Khamhaeng's mother, and möaṅ. Khun Phasit said that these terms should in fact be read as /söŋ/ and /möŋ/....
khun : ruler of a fortified town and its surrounding villages, together called a mu'ang. In older sources the prefix ph'o ("father") is sometimes used as well.
Examples of the first are söaṅ, the name of Ram Khamhaeng's mother, and möaṅ. Khun Phasit said that these terms should in fact be read as /söŋ/ and /möŋ/....
...Lord Sam Chon, the ruler of Müang Chot, came to attack Müang Tak....
Sang Sinxay entry