最近在看论文，急求下面几篇论文，请好心人帮个忙，谢谢！每篇5币

1 Gumbel, E.J. (1961).
Bivariate logistic distributions. Journal of the American Statistical Association 56, 335-349.

2 Andrich, D. (1978).
Application of a psychometric rating model to ordered categories which are scored with successive integers. Applied Psychological Measurement 2, 581-594.

3 Nuraki, E. (1992). A generalized partial credit model: Application of an EM algorithm. Applied Psychological Measurement 16, 159-176.

4 Muraki, E. (1990). Fitting a polytomous item response model to Likerttype data. Applied Psychological Measurement 14, 59-71.

5 Tutz, G. (1990). Sequential item response models with an ordered response. British Journal of Mathematical and Statistical Psychology 43, 39-55.

6 Tutz, G. (1991). Sequential models in categorical regression. Computational Statistics Data Analysis 11, 275-295