There is an online resource about grounded theory with a helpful page explaining ‘what is grounded theory‘.
Remodeling Grounded Theory
Remodeling Grounded Theory: a paper by Barney G. Glaser with the assistance of Judith Holton.
Conceptual modeling and grounded theory
SOULLIERE, D., BRITT, D. W. & MAINES, D. R. 2001. Conceptual modeling as a toolbox for grounded theorists. The Sociological Quarterly, 42, 253-269.