If you have an excellent article, you may wish to see what other articles refer to this article.
Leung, K., Lau, S., & Lam, W.-L. (April 01, 1998). Parenting Styles and Academic Achievement: A Cross-Cultural Study. Merrill-Palmer Quarterly, 44, 2, 157-72.
Since this has not been published recently, other authors have probably referenced it in their own articles.
The best search tools available to us for this type of information are Web of Science and Google Scholar.
Example:
1) Go to Web of Science.
2) Search for Parenting Styles and Academic Achievement in the title field. Search.

3) If this database has the citation (and it does). Click on the number by Times Cited to bring up other articles which have referred to this one.

4) Now I have a list of all of those citations. You can look for those that may be relevant. You can also add other search terms in the Refine Results box to narrow them down.

5) If any of those articles from the list look good, I can use the UCeLinks button to check for full-text access or to Request through Interlibrary Loan.