据我目前查到的明确指出相关性强弱分级参数的文献信息来说，

原始文献引用为

Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale, NJ: Lawrence Erlbaum Associates.Page:83

完整pdf下载

Jacob Cohen-Statistical Power Analysis for the Behavioral Sciences-Routledge (1988).pdf

相关系数 r 的强弱仅仅看系数的大小是不够的。一般来说，取绝对值后，0-0.09为无相关，0.1-0.3为弱相关，0.3-0.5为中等相关，0.5-1.0为强相关。显著性（是否显著相关）在此不讨论。

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相关论述①

The strength can be assessed by these general guidelines [1] (which may vary by discipline):

• .1 < | r | < .3 … small / weak correlation

• .3 < | r | < .5 … medium / moderate correlation

• .5 < | r | ……… large / strong correlation

[1]  Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale, NJ: Lawrence Erlbaum Associates.

http://libguides.library.kent.edu/SPSS/PearsonCorr  

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相关论述②

HOW TO INTERPRET A COR RELATION COEFFICIENT R

By Deborah J. Rumsey

In statistics, the correlation coefficient r measures the strength and direction of a linear relationship between two variables on a scatterplot. The value of r is always between +1 and –1.  To interpret its value, see which of the following values your correlation r is closest to:

http://www.dummies.com/education/math/statistics/how-to-interpret-a-correlation-coefficient-r/  

文献引用：Deborah J. Rumsey. (2011) Statistics for dummies (2nd ed.). Hoboken, NJ. Wiley Publishing.  Page: 284.

如有纰漏或错误之处，欢迎批评指正！

 后记：我个人总感觉有比Cohen, J. (1988).更早年代的参考文献，但并未找到，欢迎大家补充。