I am reading a paper and come across the following information:

 Predictor    Dependent Variable    Square R    Beta    P
     A                D                .12      .35   <0.05
     B                D                .16      .40   <0.05
     C                D                .13      .36   <0.05

Authors are using linear regression to compute the correlation between A and D, B and D and C and D, and they claim there is significant positive correlations between each and every one of them. I am confused and do not understand how can the authors draw such a conclusion with the presented data?