The LoC and ACoS glossaries along with the Guide are mutually inconsistent on the details of linking. Per Team Jordan, the correct language is:

Linking: the ability of women who can channel to combine their flows of the One Power. While the combined flow is not as great as the sum total of the individual flows, it is directed by the person who leads the link and that can be used much more precisely and to far greater effect than the individual flows could be. Men cannot link their abilities without the presence of a woman or women in the circle. Up to thirteen women can link without the presence of a man. With the addition of one man, the circle can increase to twenty-six women. Two men can take the circle to include thirty-four women, and so on until the limit of six men and sixty-six women is reached. There are links that include more men and fewer women, but except in the linking of one man and one woman, one woman and two men, or of course, two men and two women, there must always be at least one more woman in the circle than there are men. In most circles, either a man or a woman can control the link, but a man must control in the circle of seventy-two as well in mixed circles of fewer than thirteen. Although men are in general stronger in the Power than women, the strongest circles are those which contain as near as possible to equal numbers of men and women. See also: Aes Sedai.