diff --git a/hi_class.ini b/hi_class.ini
index c32de95e..41b00aa6 100644
--- a/hi_class.ini
+++ b/hi_class.ini
@@ -79,18 +79,29 @@ expansion_smg = 0.5 #this value will be overwritten using the closure equation.
     ii)   "propto_scale": all the alphas are proportional to the scale factor. Then, you have
           to provide a vector containg the factor of proportionality of each alpha and the
           initial value of the Planck Mass
-    iii)  "planck_linear": this parametrization depends on one single parameter. It was used
-          by the Planck collaboration in 1502.01590 (this reference provides all the details
-          about this parametrization)
-    iv)   "planck_exponential": this parametrization depends on two parameters. It was used
-          by the Planck collaboration in 1502.01590 (this reference provides all the details
-          about this parametrization)
+    iii)  "eft_alphas_power_law": delta_M, alpha_{K, B, T} are proportional to the scale factor to
+	  some power. Then, you have to provide a vector containg eight parameters, the four 
+	  proportionality constants and the four exponents of the scale factor. This generalize
+	  the "propto_scale" parametrization with the remarkable exception that in that case
+	  alpha_M was proportional to the scale factor, while here it is the Planck mass that
+	  scales with the scale factor
+    iv)   "eft_gammas_power_law": this parametrization uses the basis of the eft framework
+	  (Omega, gamma_i) and assumes that they are power laws of the scale factor
+	  (g1_0*pow(a,g1_exp)). You have to provide a vector containing eight parameters,
+	  the four proportionality constants and the four exponents of the scale factor
+    v)    "eft_gammas_exponential": this parametrization uses the basis of the eft framework
+	  (Omega, gamma_i) and assumes that they are exponentials in the scale factor. In a
+	  schematic way it reads: exp(gi_0*pow(a,gi_exp))-1. You have to provide a vector
+	  containing eight parameters, the four proportionality constants and the four
+	  exponents of the scale factor
     The parametrization you want to used is stored in the variable "gravity_model", while the
     value of the parameters is stored in the vector "parameters_smg"
     i)    "propto_omega" -> x_k, x_b, x_m, x_t, M*^2_ini (default)
     ii)   "propto_scale" -> x_k, x_b, x_m, x_t, M*^2_ini
-    iii)  "planck_linear" -> Omega_0
-    iv)   "planck_exponential" -> alpha_M0, beta
+    iii)  "eft_alphas_power_law" -> delta_M_0, x_k, x_b, x_t, delta_M_0_exp, x_k_exp, x_b_exp, x_t_exp
+    iv)   "eft_gammas_power_law" -> Om_0, g_1, g_2, g_3, Om_0_exp, g_1_exp, g_2_exp, g_3_exp
+    v)    "eft_gammas_exponential" -> Om_0, g_1, g_2, g_3, Om_0_exp, g_1_exp, g_2_exp, g_3_exp
+
 
 gravity_model = propto_omega
 parameters_smg = 1., 0., 0., 0., 1.
diff --git a/include/background.h b/include/background.h
index f00901bf..7c9f33a2 100755
--- a/include/background.h
+++ b/include/background.h
@@ -11,7 +11,7 @@
 #include "parser.h"
 
 enum spatial_curvature {flat,open,closed};
-enum gravity_model {propto_omega, propto_scale, planck_linear, planck_exponential}; //write here the different models
+enum gravity_model {propto_omega, propto_scale, eft_alphas_power_law, eft_gammas_power_law, eft_gammas_exponential}; //write here the different models
 
 // initial conditions for the perturbations
 enum pert_initial_conditions {single_clock, zero};
diff --git a/source/background.c b/source/background.c
index 46597a7b..7c5808bd 100755
--- a/source/background.c
+++ b/source/background.c
@@ -2195,16 +2195,17 @@ int background_initial_conditions(
 	pvecback_integration[pba->index_bi_M_pl_smg] = pba->parameters_2_smg[4];
 	break;	
 
-      case planck_linear:
-	//NOTE: The Planck collaboration decided to consider models with M_pl^2=1+\Omega. Here, even if we have an additional integration parameter (i.e. M_pl_ini), we decided to fix it to M_pl^2=1+a*Omega_0 in order to be coherent with the choice of the Planck collaboration.
-	pvecback_integration[pba->index_bi_M_pl_smg] = 1+a*pba->parameters_2_smg[0];
+      case eft_alphas_power_law:
+	pvecback_integration[pba->index_bi_M_pl_smg] = 1. + pba->parameters_2_smg[0]*pow(a, pba->parameters_2_smg[4]);
 	break;
 
-      case planck_exponential:
-	//NOTE: The Planck collaboration decided to consider models with M_pl^2=1+\Omega. Here, even if we have an additional integration parameter (i.e. M_pl_ini), we decided to fix M_pl^2=exp(alpha_M0*pow(a, beta)/beta) in order to be coherent with the choice of the Planck collaboration.
-	pvecback_integration[pba->index_bi_M_pl_smg] = exp(pba->parameters_2_smg[0]*pow(a, pba->parameters_2_smg[1])/pba->parameters_2_smg[1]);
+      case eft_gammas_power_law:
+	pvecback_integration[pba->index_bi_M_pl_smg] = 1. + pba->parameters_2_smg[0]*pow(a,pba->parameters_2_smg[4]) + pba->parameters_2_smg[3]*pow(a,pba->parameters_2_smg[7]);
 	break;
-	
+      case eft_gammas_exponential:
+	pvecback_integration[pba->index_bi_M_pl_smg] = exp(pba->parameters_2_smg[0]*pow(a,pba->parameters_2_smg[4])) + exp(pba->parameters_2_smg[3]*pow(a,pba->parameters_2_smg[7])) -1.;
+	break;
+
     }
     
       if (pba->M_pl_evolution_smg == _TRUE_)
@@ -2558,29 +2559,66 @@ int background_gravity_functions(
       pvecback[pba->index_bg_mpl_running_smg] = c_m*a;
       pvecback[pba->index_bg_M2_smg] = M_pl;
     }
-    else if (pba->gravity_model_smg == planck_linear) {	
-      //NOTE: With this parametrization every function it is expressed analytically. Then, it is possible to choose both to take the derivative of M_pl to obtain alpha_M or to integrate alpha_M to obtain M_pl. Even if the two results are undistinguishable, we choose the latter option, since in Class integrals are more stable numerically.
+    else if (pba->gravity_model_smg == eft_alphas_power_law) {	
       
-      double Omega = a*pba->parameters_2_smg[0];
+      double M_0 = pba->parameters_2_smg[0];
+      double c_k = pba->parameters_2_smg[1];
+      double c_b = pba->parameters_2_smg[2];
+      double c_t = pba->parameters_2_smg[3];      
+      double M_0_exp = pba->parameters_2_smg[4];
+      double c_k_exp = pba->parameters_2_smg[5];
+      double c_b_exp = pba->parameters_2_smg[6];
+      double c_t_exp = pba->parameters_2_smg[7];      
       
-      pvecback[pba->index_bg_tensor_excess_smg] = 0.;
-      pvecback[pba->index_bg_mpl_running_smg] = Omega/(1.+Omega);
-      pvecback[pba->index_bg_braiding_smg] = -pvecback[pba->index_bg_mpl_running_smg];
-      pvecback[pba->index_bg_kineticity_smg] = 3.*((2.+3.*Omega)*(pvecback[pba->index_bg_rho_smg]+pvecback[pba->index_bg_p_smg])+Omega*(pvecback[pba->index_bg_rho_tot_wo_smg]+pvecback[pba->index_bg_p_tot_wo_smg]))/2./(1.+Omega)/rho_tot;
+      pvecback[pba->index_bg_kineticity_smg] = c_k*pow(a, c_k_exp);
+      pvecback[pba->index_bg_braiding_smg] = c_b*pow(a, c_b_exp);	
+      pvecback[pba->index_bg_tensor_excess_smg] = c_t*pow(a, c_t_exp);
+      pvecback[pba->index_bg_mpl_running_smg] = M_0*M_0_exp*pow(a, M_0_exp)/(1. + M_0*pow(a, M_0_exp));
       pvecback[pba->index_bg_M2_smg] = M_pl;
     }
-    else if (pba->gravity_model_smg == planck_exponential) {	
-      //NOTE: With this parametrization every function it is expressed analytically. Then, it is possible to choose both to take the derivative of M_pl to obtain alpha_M or to integrate alpha_M to obtain M_pl. Even if the two results are undistinguishable, we choose the latter option, since in Class integrals are more stable numerically.
+    else if ((pba->gravity_model_smg == eft_gammas_power_law) || (pba->gravity_model_smg == eft_gammas_exponential)) {
+      
+      double Omega=0., g1=0., g2=0., g3=0., Omega_p=0., Omega_pp=0., g3_p=0.;
+      double Omega_0=0., g1_0=0., g2_0=0., g3_0=0.;
+      double Omega_exp=0., g1_exp=0., g2_exp=0., g3_exp=0.;
+      
+      Omega_0 = pba->parameters_2_smg[0];
+      g1_0 = pba->parameters_2_smg[1];
+      g2_0 = pba->parameters_2_smg[2];
+      g3_0 = pba->parameters_2_smg[3];
+      Omega_exp = pba->parameters_2_smg[4];
+      g1_exp = pba->parameters_2_smg[5];
+      g2_exp = pba->parameters_2_smg[6];
+      g3_exp = pba->parameters_2_smg[7];
+      
+      if (pba->gravity_model_smg == eft_gammas_power_law) {
+        Omega = Omega_0*pow(a,Omega_exp);
+        Omega_p = Omega_0*Omega_exp*pow(a,Omega_exp-1.); // Derivative w.r.t. the scale factor
+        Omega_pp = Omega_0*Omega_exp*(Omega_exp-1.)*pow(a,Omega_exp-2.); // Derivative w.r.t. the scale factor
+        g1 = g1_0*pow(a,g1_exp);
+        g2 = g2_0*pow(a,g2_exp);
+        g3 = g3_0*pow(a,g3_exp);
+        g3_p = g3_0*g3_exp*pow(a,g3_exp-1.); // Derivative w.r.t. the scale factor
+      }
+      else { //(pba->gravity_model_smg == eft_gammas_exponential)
+        Omega = exp(Omega_0*pow(a,Omega_exp))-1.;
+        Omega_p = Omega_0*Omega_exp*pow(a,Omega_exp-1.)*exp(Omega_0*pow(a,Omega_exp)); // Derivative w.r.t. the scale factor
+        Omega_pp = Omega_0*Omega_exp*pow(a,Omega_exp-2.)*exp(Omega_0*pow(a,Omega_exp))*(Omega_exp-1.+Omega_0*Omega_exp*pow(a,Omega_exp)); // Derivative w.r.t. the scale factor
+        g1 = exp(g1_0*pow(a,g1_exp))-1.;
+        g2 = exp(g2_0*pow(a,g2_exp))-1.;
+        g3 = exp(g3_0*pow(a,g3_exp))-1.;
+        g3_p = g3_0*g3_exp*pow(a,g3_exp-1.)*exp(g3_0*pow(a,g3_exp)); // Derivative w.r.t. the scale factor
+      }
+      
       
-      double alpha_M0 = pba->parameters_2_smg[0];
-      double beta = pba->parameters_2_smg[1];
-      double Omega = exp(alpha_M0*pow(a, beta)/beta)-1;
+      double c_over_H2 = (-pow(a,2.)*Omega_pp + 3.*(Omega + a*Omega_p/2.)*(rho_tot + p_tot)/rho_tot + 3.*(pvecback[pba->index_bg_rho_smg]+pvecback[pba->index_bg_p_smg])/rho_tot)/2.;
       
-      pvecback[pba->index_bg_tensor_excess_smg] = 0;
-      pvecback[pba->index_bg_mpl_running_smg] = alpha_M0*pow(a, beta);
-      pvecback[pba->index_bg_braiding_smg] = -pvecback[pba->index_bg_mpl_running_smg];
-      pvecback[pba->index_bg_kineticity_smg] = (1-beta-pvecback[pba->index_bg_mpl_running_smg])*pvecback[pba->index_bg_mpl_running_smg] + 3*(2+pvecback[pba->index_bg_mpl_running_smg])*(pvecback[pba->index_bg_rho_smg]+pvecback[pba->index_bg_p_smg])/2/rho_tot + 3*(pvecback[pba->index_bg_mpl_running_smg]+2*Omega/(1+Omega))*(pvecback[pba->index_bg_rho_tot_wo_smg]+pvecback[pba->index_bg_p_tot_wo_smg])/2/rho_tot;
+      pvecback[pba->index_bg_kineticity_smg] = 2.*(2.*g1*pow(pba->H0,2.)/rho_tot + c_over_H2)/(1. + Omega + g3);
+      pvecback[pba->index_bg_braiding_smg] = -(g2*pba->H0/sqrt(rho_tot) + a*Omega_p)/(1. + Omega + g3);
+      pvecback[pba->index_bg_tensor_excess_smg] = -g3/(1. + Omega + g3);
+      pvecback[pba->index_bg_mpl_running_smg] = a*(Omega_p + g3_p)/(1. + Omega + g3);
       pvecback[pba->index_bg_M2_smg] = M_pl;
+
     }
     
     
@@ -2645,10 +2683,23 @@ int background_gravity_parameters(
 	    pba->parameters_2_smg[4]);
      break;
 
-   case planck_linear:
-     printf("Modified gravity: planck_linear with parameters: \n");
-     printf("-> Omega_0 = %g \n",
-	    pba->parameters_2_smg[0]);
+   case eft_alphas_power_law:
+     printf("Modified gravity: eft_alphas_power_law with parameters: \n");
+     printf("-> M_*^2_0 = %g, c_K = %g, c_B = %g, c_T = %g, M_*^2_exp = %g, c_K_exp = %g, c_B_exp = %g, c_T_exp = %g\n",
+	    pba->parameters_2_smg[0],pba->parameters_2_smg[1],pba->parameters_2_smg[2],pba->parameters_2_smg[3],
+	    pba->parameters_2_smg[4],pba->parameters_2_smg[5],pba->parameters_2_smg[6],pba->parameters_2_smg[7]);
+     break;
+
+   case eft_gammas_power_law:
+     printf("Modified gravity: eft_gammas_power_law with parameters: \n");
+     printf("-> Omega_0 = %g, gamma_1 = %g, gamma_2 = %g, gamma_3 = %g, Omega_0_exp = %g, gamma_1_exp = %g, gamma_2_exp = %g, gamma_3_exp = %g \n",
+	    pba->parameters_2_smg[0],pba->parameters_2_smg[1],pba->parameters_2_smg[2],pba->parameters_2_smg[3],pba->parameters_2_smg[4],pba->parameters_2_smg[5],pba->parameters_2_smg[6],pba->parameters_2_smg[7]);
+     break;
+
+   case eft_gammas_exponential:
+     printf("Modified gravity: eft_gammas_exponential with parameters: \n");
+     printf("-> Omega_0 = %g, gamma_1 = %g, gamma_2 = %g, gamma_3 = %g, Omega_0_exp = %g, gamma_1_exp = %g, gamma_2_exp = %g, gamma_3_exp = %g \n",
+	    pba->parameters_2_smg[0],pba->parameters_2_smg[1],pba->parameters_2_smg[2],pba->parameters_2_smg[3],pba->parameters_2_smg[4],pba->parameters_2_smg[5],pba->parameters_2_smg[6],pba->parameters_2_smg[7]);
      break;
 
     
diff --git a/source/input.c b/source/input.c
index 4a75ebce..935bf5c7 100755
--- a/source/input.c
+++ b/source/input.c
@@ -1041,28 +1041,37 @@ int input_read_parameters(
 	class_read_list_of_doubles("parameters_smg",pba->parameters_2_smg,pba->parameters_2_size_smg);
       }
       
-      if (strcmp(string1,"planck_linear") == 0) {
-	pba->gravity_model_smg = planck_linear;
+      if (strcmp(string1,"eft_alphas_power_law") == 0) {
+	pba->gravity_model_smg = eft_alphas_power_law;
 	pba->field_evolution_smg = _FALSE_;
 	pba->M_pl_evolution_smg = _TRUE_;
 	flag2=_TRUE_;
-	pba->parameters_2_size_smg = 1;
+	pba->parameters_2_size_smg = 8;
 	class_read_list_of_doubles("parameters_smg",pba->parameters_2_smg,pba->parameters_2_size_smg);
       }
 
-      if (strcmp(string1,"planck_exponential") == 0) {
-	pba->gravity_model_smg = planck_exponential;
+      if (strcmp(string1,"eft_gammas_power_law") == 0) {
+	pba->gravity_model_smg = eft_gammas_power_law;
 	pba->field_evolution_smg = _FALSE_;
 	pba->M_pl_evolution_smg = _TRUE_;
 	flag2=_TRUE_;
-	pba->parameters_2_size_smg = 2;
+	pba->parameters_2_size_smg = 8;
 	class_read_list_of_doubles("parameters_smg",pba->parameters_2_smg,pba->parameters_2_size_smg);
       }
-	
+
+      if (strcmp(string1,"eft_gammas_exponential") == 0) {
+	pba->gravity_model_smg = eft_gammas_exponential;
+	pba->field_evolution_smg = _FALSE_;
+	pba->M_pl_evolution_smg = _TRUE_;
+	flag2=_TRUE_;
+	pba->parameters_2_size_smg = 8;
+	class_read_list_of_doubles("parameters_smg",pba->parameters_2_smg,pba->parameters_2_size_smg);
+      }
+
 
       class_test(flag2==_FALSE_,
 		 errmsg,
-		 "could not identify gravity_theory value, check that it is one of 'propto_omega', 'propto_scale', 'planck_linear', 'planck_exponential' ...");
+		 "could not identify gravity_theory value, check that it is one of 'propto_omega', 'propto_scale', 'eft_alphas_power_law', 'eft_gammas_power_law', 'eft_gammas_exponential' ...");
       
     }// end of loop over models