Sovietwarplanes

Hello all,
I have in my stock a Special Hobby I-15 "Chato" and I would like to build a Republican Spanish Civil War Ace aircraft.
I decided for an aircraft flown by Leopoldo Morquillas Rubio and I found some information.
But I need your advice and your knowledges about it.
Here are the infos I found => I-15 "Chato" "white 57" flown by L. Morquillas Rubio during Summer 1937, O.C. Escuadrilla de Caza del Norte.
(http://i744.photobucket.com/albums/xx84/le_steph40/Capture_zpsn6azwnpr.jpg)
I found infos about this aircraft here http://surfcity.kund.dalnet.se/spain_morquillas.htm (http://surfcity.kund.dalnet.se/spain_morquillas.htm)
On this website, it is said "CA-57", and I ask myself if there is only "white 57" marking on the rudder or if there another "CA-57" marking on the fuselage too...?

Other info, and other photo => I-15 "Chato" "white 15" flown by L. Morquillas Rubio early in 1938, O.C. 2a Escuadrilla de Caza. Effectively, the triangle is the symbol for 2a escuadrilla O.C. (a circle for the 1a, a square for the 3a and a double circle for the 4a)
(http://i744.photobucket.com/albums/xx84/le_steph40/Morquillas%20Rubio%20L.-I15%20O.C.2esc%20dbut%201938_1_zps8rurb7lr.jpg)
(http://i744.photobucket.com/albums/xx84/le_steph40/Morquillas%20Rubio%20L.-I15%20O.C.2esc%20dbut%201938_zpstx0prs0l.jpg)
I found the archive photo in a Russian book "КОМБАТ N°1: ИСТРЕБИТЕЛЬ И-15" page 38, photo 63. This source and some others say it's Morquillas Rubio aircraft when he was O.C. 2a Escuadrilla de Caza early in 1938. But I found other sources which statued that this aircraft is the one of the O.C. 2a escuadrilla de Caza during Spring 1937. In this case, this aircrat is the one flown by Roberto Alonso Santamaria due the period... If we look at the photo, we see the shadow of the aircraft on the floor, dry land and leaves in the trees... I know it's often sunny weather in Spain but, early in 1938, it's winter...!!!

Anybody to help me please ? TIA.
Regards
Stéph