WANG, J., & CHEN, C. (2000). SINGULAR POINTS AND LIE ROTATED VECTOR FIELDS. International Journal of Mathematics and Mathematical Sciences, 2000(), a179-185-126. https://doi.org/10.1155/S016117120001005X
Ozok, A. K. (1981). ON RELATED VECTOR FIELDS OF CAPILLARY SURFACES. International Journal of Mathematics and Mathematical Sciences, 1981(), 473-484. https://doi.org/10.1155/S0161171281000331