The Gasoline code contains a number of components that have been outlined in a number of publications. If you want to understand the internal mechanisms of Gasoline, you should start here.
Gasoline2: A Modern SPH Code
Wadsley, James W.; Keller, Benjamin W.; Quinn, Thomas R. (2017)
This is the paper that describes the current state of the SPH method used in Gasoline. The public release began with this publication
A superbubble feedback model for galaxy simulations
Keller, B. W.; Wadsley, J.; Benincasa, S. M.; Couchman, H. M. P. (2014)
The newer "Superbubble" model for supernova feedback is described, along with some preliminary Gasoline2 features, in this paper.
Implementing molecular hydrogen in hydrodynamic simulations of galaxy formation
Christensen, Charlotte; Quinn, Thomas; Governato, Fabio; Stilp, Adrienne; Shen, Sijing; Wadsley, James
The molecular hydrogen cooling and star formation components in Gasoline are described in this paper
The First Massive Black Hole Seeds and Their Hosts
Bellovary, Jillian; Volonteri, Marta; Governato, Fabio; Shen, Sijing; Quinn, Thomas; Wadsley, James
The black hole seed formation code is described in this paper.
The enrichment of the intergalacitc medium with adiabatic feedback - I. Metal cooling and metal diffusion
Shen, S.; Wadsley, J.; Stinson, G. (2010)
The metal line cooling, as well as the Smagorinsky mixing estimator, are described in this paper
On the treatment of entropy mixing in numerical cosmology
Wadsley, J. W.; Veeravalli, G.; Couchman, H. M. P. (2008)
The artificial diffusion model used in gasoline was first described in this paper
Star formation and feedback in smoothed particle hydrodynamic simulations - I. Isolated galaxies
Stinson, Greg; Seth, Anil; Katz, Neal; Wadsley, James; Governato, Fabio; Quinn, Tom (2006)
This paper describes the basic star formation recipe used in Gasoline, as well as the cooling-shutoff based "Blastwave" supernova feedback model.
Gasoline: a flexible, parallel implementation of TreeSPH
Wadsley, J. W.; Stadel, J.; Quinn, T. (2004)
This is the original code paper that describes the first version of Gasoline. Much of the internal architecture is described here.