Hayanaratna 8.75

Next, the month results, from the Varsha Tantra. At the time of the month entry too, one should work out the great houses. There, the lord of the month's lagna (rising sign) is one candidate. So are the lord of the muntha (the point that moves one sign each year) and the birth lord.

Simple meaning: Month results: cast the month chart. The candidates for month lord are the lords of the month lagna, the muntha and the birth lagna.