fix citation

Author: ranocha

paper/paper.md

@@ -48,7 +48,7 @@ Unfortunately, these new methods are not yet available in software packages, mak
 # Features
 
 PositiveIntegrators.jl is written in Julia [@bezanson2017julia] and makes use of its strengths for scientific computing, e.g., ease of use and performance.
-The package is fully compatible with DifferentialEquations.jl [@rackauckas2017differentialequations] and therefore many features that are available there can be used directly. In particular, this allows a direct comparison of MPRK and standard schemes. Moreover, it integrates well with the Julia ecosystem, e.g., by making it simple to visualize numerical solutions using dense output in Plots.jl [christ2023plots].
+The package is fully compatible with DifferentialEquations.jl [@rackauckas2017differentialequations] and therefore many features that are available there can be used directly. In particular, this allows a direct comparison of MPRK and standard schemes. Moreover, it integrates well with the Julia ecosystem, e.g., by making it simple to visualize numerical solutions using dense output in Plots.jl [@christ2023plots].
 
 The package offers implementations of conservative as well as non-conservative production-destruction systems (PDS), which are the building blocks for the solution of differential equations with MPRK schemes. Furthermore, conversions of these PDS to standard `ODEProblem`s from DifferentialEquations.jl are provided.