Multi-species collisions for delta-f gyrokinetic simulations: Implementation and verification with GENE. - Paul Crandall; Denis Jarema; Hauke Doerk; Qingjiang Pan; Gabriele Merlo; Tobias Görler; Alejandro Bañón Navarro; Daniel Told; Maurice Maurer; Frank Jenko (Comput. Phys. Commun., 2020)