https://doi.org/10.1351/goldbook.A00353

Angular momentum, or moment of momentum of a particle about a point is a vector quantity equal to the vector product of the position vector of the particle and its momentum, L = r x p. For special angular momenta of particles in atomic and molecular physics different symbols are used.*Source: *

Green Book, 2^{nd} ed., p. 12 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

Green Book, 2